So, what is Ice-type?
As discussed before, though in Western RPGs Ice became relevant much later, due to Final Fantasy's decision to use Ice-Fire-Electric triangle, Ice became a staple for JRPGs. This is very much true for Pokémon as well, as Ice is one of the archetypical elements of the game. However, compared to other archetypical elements, it is the most poorly represented one. While many Pokémon of different types get access to Fire and Electric moves, Ice is more or less exclusive to Water, Dragon and Normal type Pokémon. This creates an odd scenario where Ice is simultaneously both an archetypical type, and isn't. Ice-type is also the only type associated with a non-volatile status that cannot simply inflict that status, Freeze. This is because freezing is the most powerful status move, but it is also the one that has some ways around it, like Flare Blitz, Scald, and Flame Wheel.
This is not too unexpected considering how rare Ice is normally in our contemporary era. However, this causes Ice to continue to suffer as one of the worst types that works subservient to another type, Water, the single most abundant type. Until a proper demarcation between Ice and Water occurs, it is hard to say where Ice will go.
The History of Ice-type in Pokémon:
The first generation of Ice-types was, for all intents and purposes, good. Initially Ice was neutral against its nemesis Fire-type. This meant you could totally freeze Charizard(reference completely intended btw.) With the absence of a Steel-type as well, Ice-type had four major offensive targets, and only two resisting types, Water and Ice. This made Ice, alongside Psychic, the best offensive type in the game. To compensate this, most Ice-types were made largely bulky species with lesser Special Attack than their Water brethren.
The first generation of Ice-types were also generous in their moves as well, as most of the current popular Ice-type moves wee created back then. While Ice-types that weren't Water-type were stuck with weak Water moves, those who are were blessed with neutrality against their nemesis the Fire-types. The association between Ice and Water were heavily showcased, from Seafoam Islands to Lorelei-Misty connection to TCG, to Lapras itself, the second earliest Ice-type you can get in the game, and one of Red's canon Pokémon.
In the following generation, the dream ended for two major reasons. One was the Special split, where most of the Special stats originally given to Ice-types were largely given to their Special Defense, which sealed Ice-type's role as a balanced type, rather than an offensive type like Fire. This also retroactively made powerful Ice-types of Generation I to much weaker and average species, as the compensation they gained was much weaker(except for Jynx). The second major blow was the introduction of Steel and change to the type chart. Ice no longer hit Fire neutrally, and was walled by and hit powerfully by the Steel-type. To compensate for this Steel was made weak to Fire and resisted by Water. However, the damage was done, and Ice was effectively made into a weaker counterpart to Fire.
Another nail on the coffin of Ice-types was Pryce. Serving as semi-final gym leader, Pryce's Pokémon were meant to be not powerful compared to the titans you will face in the Kanto. However, since Pryce's Pokémon were to be found in the Ice Path, the only Ice-type area in Johto, this meant all Johto Ice-types were designed explicitly, well, suck. Pryce's presence also sealed Ice-type's role in other manner, as Ice-types were now designated as the late game type. While this was true for Kanto as well, in Kanto, Ice-type was a (lesser) E4 tier type with two optional members available early, Lapras around fifth Gym in Silph Co., and Jynx in Cerulean City as trade. This, however, sealed Ice-type's role as a near-end game type, with no counterparts for post-game, or Victory Road(though Sneasel would reside in Route 28 and Alola would later bring Ice-type to Mount Lanakila, the game's counterpart to Victory Road). Because of this Ice-type was given odd role to suck enough for pre-end-game, while being powerful enough for end-game.
And also, fuck Delibird. Seriously.
The third generation for Ice-types, well, bad. It is Hoenn, after all, and Kyushu the only Ice-type you will hear is your Catholic mom's freezer. Nonetheless, since Hoenn was a carbon copy of the first generation of Pokémon, we still managed to have an Ice-type Elite Four and Ice-type legendary. Walrein was interesting case, as it was a counterpart of a two-stage Pokémon, and because of Glacia, had to have a pre-evolution with acceptable stats to that time. Glalie was another interesting case, it was only accessible in certain times of the day... in a game with no day and night cycle.
And of course abilities. Ice-type didn't gain much stuff related to themselves. Some gained Inner Focus, some gained Thick Fat, some gained Shell Armor. Because Hail was just recently introduced, unlike other types, they had no Abilities to match with this new weather. Sadly the new weather did not save the Ice-type, but at least it tried.
Fourth generation was something of a hidden renaissance for Ice-types... when it was supposed to be a true renaissance for Ice-types because Sinnoh is the only region dedicated to them. Again, Pryce clause. Anyways, the new Hail was finally integrated into Ice-types, with several Ice-types gaining Ice Body and Snow Cloak, new abilities introduced to make use of this new weather. Other Ice-types also gained unrelated secondary abilities, making Ice one of the few types where most everyone got a full set of abilities. This generation also introduced two major cross-generational evolutions and two side evolutions to make up for the previous mistakes in the older generations.
In addition to these we got a new line to match Tyranitar, Snover-line, with Snow Warning, insta Hail setting ability, and tons of new moves due to Physical-Special split in the form of Avalanche, Ice Fang and Ice Shard. In addition, two of the moves from previous generation were also retconned to Physical, to give edge to the Physical Ice-types.
Fifth generation was another surge for Ice-types. While they were stuck to Pryce clause, there was finally another Ice-type you could obtain near fifth Gym, Vanillite. In addition, another strong Physical Ice-type move was introduced. However, the biggest introductions were Kyurem itself, the second strongest legendary of that time, and Hidden Abilities, which allowed other Pokémon to get new abilities, some related to the type, others not.
This generation also introduced seasons to make Ice-types more common in Winter, but that hardly effected things.
In sixth generation, Ice-types were put into the freezer. The type gained two new Pokémon and two new Megas, and a new ability Refrigerate, and one new cool move, Freeze-Dry. Freeze-Dry allowed Ice-types to bypass Water-types.
This was an odd thing despite Kalos' focus on Ice, and Hoenn's remake, but it happened regardless. This was another lost generation for Ice-type.
In the seventh generation, Ice-types gained several janitorial buffs. The tropical nature of Alola meant that the only good Ice-types you would gain would be end-game, however, this generation brought in large stat boosts to Unovan Ice-types, one new species, two families of regional variants, Slush Rush, Aurora Veil and Ice Hammer, and Snow Warning to Vanilluxe.
The Overview of Ice-types:
Ice-types are bad. Don't use them.
Okay, let's rewind that a bit. Ice-types served two major purposes, replacing Water for end-game and defeating the strongest type, Dragons. The former failed because Water simply superseded Ice-types, and the latter failed because Fairies were introduced. Currently Ice-type serves only one serve one purpose, hitting types for quad weakness. This is as true for conventional Ice-type moves as it is for Freeze-Dry.
It is hard to say if Ice-type would be success if it retained the old type chart, or gained several resistances like to Ground and Dragon, or an immunity to a new type. Whatever might happen to Ice-type, it needs something to make it relevant again.
Another issue regarding Ice-type is its aggressively balanced nature. This is supposed to mimic real life arctic and tundra animals, of course, and it is not too apparent for non-organic ones(which suffer other issues), but this causes issues for a type that is explicitly designed to be glass cannon, both metaphorically and literally.
Another another issue the Pryce discussed above. Ice-type might have had some success as an early route type(though attempts in Pokémon Sage and Clover seem to confirm that this won't be the case, Ice-type is really just that terrible) but this causes an issue for its rarity, even in regions like Kalos and Sinnoh where it really shouldn't be.
Ice-type also severely needs powerful Water-types that are not lolBubbleBeam and Water Pulse, the connection between the two types need to work for both ways, or Ice-type should gain more light based moves besides Flash Cannon and Signal Beam.