I know competitive isn't THE number one thing to think about when it comes to pokemon but I've got talk about mega feraligatr. 
(just a word of warning, I am by no means an expert on this kind of thing, this is just what I think might happen.)
For starters (ha!) it's stat distribution. Overall it seems very good. That monstrous 160 attack is a massive improvement from normal feraligatr and also a respectable 125 defence too makes him much bulkier
He also got some points to his special bulk which is helpful but the only thing I think wasn't good was a 10 point boost to his special attack... Why game freak. Just why? He's basically never going to use special attacks you could have just put those into his special bulk as well?

Anyway He's also dragon type now meaning he's no longer weak to grass, only dragon and fairy which is nice I'd say. Although with all the powerful fairy types nowadays it might actually be a problem. 

Regardless what are stats and typing without moves? Well he's actually got some amazing stuff.
He gets liquidation, trailblaze for other water types, earthquake for spread, ice fang (this'll be important for later) crunch, DRAGON DANCE AND SCALE SHOT which is now stab. Flip turn for easy switching and some other things. All that combined with his new attack stat and most things probably won't survive. 

Now for it's ability. I have two guesses her. Either it'll keep sheer force which would still be really good even if he can't abuse life orb for free power anymore (although I think the new stats remedy that somewhat)

OR
Considering his design, it'll get strong jaw, bringing it one move away from basically making it Dracovish 2.0.

Honestly I think it would be better if it kept sheer force but only time will tell. 

Now right now I can imagine his main set will be pretty similar to how it was previously. 
Investing into his speed start with a speed boosting nature on top with likely some attack a defence on the side. 

Moves will probably be dragon dance to set up, liquidation for stab and damage, with scale shot or ice fang probably in there for dragons depending on if it gets strong jaw or not (although scale shot might still be better)
And either protect or earthquake depending on if you want to just kill everything or be a bit more careful and let it's partner do the spread damage. 

Again, I'm nowhere near an expert on this stuff, this is just what my gut is telling me for when champions finally releases and competitive moves there. 

Mega feraligatr and it's potential