>>14399010It's getting a Mega Form in this game, which, if you don't know what that is, means a new model/boosted stats/changed ability.
Before this gen, it was always pretty low-tier in stats. I doubt they'll upgrade its base form's stats, but Mega Mawile should be plenty of a substitute for that. It's fine to get you through the game regardless, it just won't get you very far in the competitive field, which may be something you don't care about.
I'm of the mind that if you like a pokemon, you should use it, personally.
Other than that, it's not super tanky but her steel typing helps. It's got decent attack (NOT special attack, though), and its Mega Form's ability will double its attack, which is nice.
Only real advice I can give is to look over this thread for some advice on moves, and don't expect a special attacker out of it.