Too bad the power got nerfed this gen, I was really wanting to try out some variant of the Gen IV Passho BOOM Steelix to kill bulky waters. Except that now, you don't need the Passho with Sturdy.
Sadly that is probably the only relevant thing Steelix can do this Gen outside of enjoying the troll factor of Heavy Slam (which still sucks). It's offenses are sub-par (base 85 attack with only one relevant STAB and base 30 speed) and it can't wall crap. It has a trollishly useless base defense (200 means nothing if you're weak to the most powerful and common physical attacks in the game) and its sp def makes you happy it gets sturdy so you can get SR up. Woot :/