>>47077724Steelix already has curse which is better than coil for this mon.
The only way to make Steelix better is to give it better abilities. It already has a good movepool. A mix of supporting and offensive moves. Maybe give him Volt Tackle to hit waters? Wild Charge isn't going to do much off of 85 base attack.
But as a steel type his competition is Melmetal, Empoleon, Registeel, Doublade and klefki as bulky pivots, Stakataka as a trick room sweeper, Silvally Steel as a sort of supporty momentum pivot and even Aggron for meme sets like DUDE CB HEADSMASH LMAO XD.
That ground typing is a glaring weakness for Steelix. Slow defensive groundtypes is not a good niche in this game. It's actively setting him back compared to the rest of the steel types. I feel like no matter what you do with Steelix he just wants to be like a mix of Melmetal and Tyranitar. But through a mix of typing, BST, stat distribution, abilities and lack of coverage he will never reach those heights. And his niche in a team is often to setup rocks and die which a lot of teams appreciate and that's where he sees his use.