Lack of recovery very much hurts it, as does a x4 weakness to Steel, which makes it pretty much useless in OU, which is the tier to really strive for. Scizor has been a top OU Pokemon for two generations now, and there is really nothing in this Gen that can disrupt that dominance, while instead it will probably be all the more powerful since it has a new type it is Super Effective against and it got a Mega Evolution. We also have Mega Lucario, whose Bullet Punch is only slightly weaker than Mega Scizor's and will probably see a fair amount of use with that solid speed and devastating Close Combat.
It will probably be best used as a supporting wall in whatever tier it is put in, but in my use of it, I would not call it a very good wall, mainly for that x4 weakness to Steel. It also does not help that because it won't perform well in OU, it will have less of a way to make use of that Dragon immunity, because you see less and less Dragons as you go down in tiers.