No, they shouldn't change the level cap, I mean seriously, most Pokemon learn all their moves by level 80 and well all it is doing after that is raising their stats by two or three points, kinda pointless to make the level cap higher if you ask me, 100 is good. And the majority of players, hardcore or not will agree, there is only a few people that don't, because imo, trying to get a Pokemon to level 170 if they've learned all their moves by level 80 would probably tend to get boring. I don't know, but I think the level cap is fine as it is.
And battles won't change that much besides needing more experience to get their, you'll just have players with level 175 Legendaries instead of level 100, rather pointless if you ask me.