Before putting in a mega evolution, I'd address your pretty crippling Rotom-W weakness. Noivern is a "check" but is pretty awful at it when sand, SR, LO recoil, and a potential burn will all eat away at its health even if it somehow avoids Rotom's STAB attacks. This gives rise to the more general weakness to stall as a whole, as Quagsire can wall your boosters, Garchomp can't break much of anything locked into attacks, and Noivern and Tyranitar don't hit hard enough and wear down easily.
To help with stall, I'd run Mega Medicham or Mega Heracross to break open their defensive core. They're also good against bulky teams even though offense is a harder match-up.
I think the real shoe to drop on this team is replacing one of your sweepers, probably the slow and punchless Scizor, with something that can actually absorb status. Magic Guard Clefable (Calm Mind) is always a solid choice for this role. You really can't afford to be weak to a staple like Rotom though.
Why are the beautiful sick and divided like myself?