Cresselia to rise to A+: yes. It's the best at what it does
Diancie to rise to A+: yes. Extremely good end-game sweeper, and Diamond Storm off 160 Atk is awesome.
Keldeo to rise to A-: yes. No Mega Mence is good for it.
Mawile to drop to A: no. It's very good both inside and outside TR
Azumarill to rise to A: yes. It's ferocious with a Belly Drum
Tyranitar to drop to A-: yes. See my previous post.
Aegislash to rise to A+: yes. Very easy to fit onto a team with what is arguably the best defensive typing in the game backed up by very good stats. And easily the best Wide Guard user.
Lucario to rise to A-: no. There are better Steel-type Mega evolutions, particularly in the bulk department.
Jirachi to drop to A-: yes. Still great; it's just not as useful now that Mega Mence is gone.
Venusaur to rise to A: no. Sun isn't what it used to be, and the Mega set competes with Ferrothorn who doesn't need a Mega slot.
Hydreigon to rise to A: no. Yes it threatens pretty much the entire metagame, but it's not too hard to check either with its weaknesses and Speed
Scizor to rise to A-: no. There are better Steel-types both including and excluding Mega evolutions. You want a Bullet Punch user, Mega Metagross is an all-round better user. It also resists Diamond Storm in case you were planning on using it to check Diancie.
Lucario to rise to A-: no, its really frail and with bad speed, although it has some okay typing. 252+ Atk Technician Breloom Mach Punch vs. 0 HP / 4 Def Lucario: 288-342 (102.4 - 121.7%) -- guaranteed OHKO
Not really relevant, as the best thing about Lucario is its Mega evolution
252+ Atk Technician Breloom Mach Punch vs. 0 HP / 0 Def Mega Lucario: 240-284 (85.4 - 101%) -- 12.5% chance to OHKO
But yeah I agree it shouldn't rise