>>26729603She's not awful. Well, I mean, she's awful, but not like, Delibird awful.
She makes for a decent, no frills physical statbrick in PU. Both Intimidate and Sheer Force are quite handy, and she gets a number of nice moves as of recently, her Movepool may not be quite as deep as some, but it dings a lot of important points.
A Sheer Force Life Orb Set with Play Rough, Iron Head, Crunch/Sucker Punch, and your coverage move of choce would work nicely as a Wallbreaker of sorts. Just make sure the wall she's trying to break won't OHKO her with a Stab Special move before she can act. The likes of Toarkoal, Grumpig, and Walrein come to mind. She hits ridiculously hard though, hard enough to break even specially defensive Avalugg in two hits with Iron Head. If it comes in on her, or flinches, it's doomed.
Intimidate+Lefties with Play Rough, Pain Split, Substitute, and Stockpile could serve as a decent enough physical tank. Her awful HP makes Pain Split a rather nice option, though unless you get those Stockpiles up, a Volt Switch or something carried by an otherwise physical attacker can to scary things to your hP bar.
Intimidate+Stealth Rock, Knock Off, Toxic, and Taunt could serve as an offensive support.
You could also try for a Sword+Sub+Pass to someone else if you want a team support Mawile, using her typing and Intimidate to make an opening. She's probably not fast or naturally bulky enough to give both, though
Mawile has lots of options, but her poor speed and special defense, coupled with poor HP makes her tough to keep alive. A good special, neutral Stab will certainly kill her, much less a great one.