One of the core aspects of any Pokémon is their typing. Whether they are a mono or dual-type and what those types are help determine both how one uses the Pokémon and how good the creature is in general. This is because not all types are equal. Certain types, such as Ice, are often a liability, as it is the worst defensive type in all the game -- so what could change that?
The big problem Ice has as a defensive typing is that it only resists itself while simultaneously being weak to Fire, Fighting, Rock and Steel. This means that it's both unable to resist much, but it's also vulnerable to some of the most common offensive types in the game. While Ice is a very good offensive typing, its lack of defensive utility means a player is more likely to teach another Pokémon an Ice-type move than to inclue an Ice-type on their team.
Adding even one additional resistance to the Ice type could really breathe new life into it, but it is important to also look at balancing the other type to not make it too weak. One option would be to make Ice resist Water, making another pair of typings that resist one another. While this would make the Water type worse offensively, it would still be better off than a type like Poison, and it has always been a relatively defensive typing anyway.
Another option could be giving Ice resistance to Flying for many of the same reasons as Water, though flying is weak to Stealth Rock, making it worse competitively in many instances. Finally, while it doesn't make the most sense, Ice becoming resistant to Ghost could be good, as Ghost currently has only one resistance and one immunity in Dark and Normal, respectively, making it a great offensive typing, better even than Dragon as it is super-effective to both Ghost and Psychic. Giving Ice one of these resistances could really bring it out of mediocrity.
One other way to make the Ice-type stronger is to make their weather better. As of now, the only bonus Ice types in general get is not taking damage from the hail. Certain Pokémon have abilities that give them bonuses during hail, but in comparison, sandstorm gives all Rock-type Pokémon a 50% bonus to their special defense. Giving hail the same benefit would help bring the weather in line with others while not making it too powerful, as only Ice-types get a bonus from it, unlike sandstorm benefits has Rock, Ground and Steel.
It's unclear whether future Pokémon games will ever make changes to the Ice-type, or any others for that matter. The popularity of Ice offensively could hold it back, but that doesn't mean it isn't possible. As was shown with changes to Steel-type and introduction of the Fairy-type, Game Freak is willing to adjust the overall type chart to give and take weaknesses and resistances in ways that balance the game.