Uh... For some reason I'm bothered by this is uh... Where did the immunity come from again...?We were talking about this on irc for a bit before it got stupid, but I dont think Mega Sceptile should jump up any tiers. If anything it should drop from B+.. the sword's dance set comes with a large amount of 4MSS- personally i dont really see it as anything past a lure set because Mega Sceptile is sword's dancing off a very unremarkable 110 base stat, is highly prone to revenge killing and still struggles with bulky mons due to disappointing BP on physical moves. Not to mention that checks to the special set become even more successful at checking the sword's dance set, with even spd forretress and umbreon both loving the non-inclusion of focus blast and hitting for 73% and 145% with gyro ball and +2 foul play respectively. The only thing that SD Mega Sceptile does much better than regular mega sceptile is lure in florges and ko with +2 iron tail, but even that is iffy when florges ohkos back with uninvested moonblast, and iffy accuracy on iron tail paired with sceptile's perhaps unfortunate STAB combo which leaves him in heavy requirement for coverage moves. He also can boost to take out suicune, but ice beam is common and will destroy sceptile and even burns can deal with the physical set. uninvested seed bomb is not a 2hko, which is also depressing. hopefully we can put physical mega sceptile to rest as not only does it find it hard to find places to boost, it also is forced out with ease and is easily dealt with after the initial surprise factor- plus sceptile has only gotten worse with the introduction of mamoswine who heavily checks him, and mandibuzz who is a straight-up counter. Alakazam and Hippowdon also left and these are two mons which mega sceptile was arguably good against, hitting hippo super effectively and outspeeding alakazam.
I dunno if Mega Sceptile should drop to B because it still performs okay as a sweeper and mixed wallbreaker and has 2 4x resists and an immunity but it is kinda underwhelming, takes up a mega slot and arguably also competes with two very big contenders for the "dragon slot" on your team since hydreigon and salamence are really great atm and it doesnt need great to stack such heavy ice weaknesses with mamo in such a good place (or just in general..).
Honestly, Mega Sceptile should drop because Mega Aboma does it's job better physically and specially, a lot of things that are popular right now screw it over(Hi Florges).