Mega Banette is fast becoming one of my favourite Mega-evolutions, but I can't help but be a little disappointed at how discombobulated it is. Despite being support oriented, the lion's share of the stat boost got dumped into attacking stats, so the idea seemed to be to wreak havoc with your newly boosted attack and deal as much damage as possible while crippling opponents, and leave a parting gift in the form of priority Destiny Bond.
In practice though, Banette's barren offensive movepool makes getting even one KO difficult, functioning instead as a kind of worse Sableye with a trade-one-for-one panic button if all else fails.
I wonder how much better it would have been if Mega Banette had been Ghost/Dark type. Now, it wields a bone-crushingly powerful STAB Sucker Punch and Pursuit to put Psychic types and fellow Ghosts into a checkmate position, making it a lot easier to relieve the opponent of at least two of their Pokemon. The threat of a strong Sucker Punch also dissuades the opponent from attacking, meaning you don't have to run Protect to survive at least one turn to activate Prankster.
I would have loved to see a Ghost/Dark-type Mega Banette; it certainly looks like it could be part Dark-type, especially with its vengeful backstory. It'd help Sucker Punch an awful lot, but it also wouldn't be too broken, considering the type combo's newfound Fairy weakness.
On a different note, how terrifying would Porygon-Z be if it had Boomburst? Imagine that coming off base 135 Sp. Attack with Adaptability. OUCH.
What if Garchomp learned Dragon Dance?
Or if Spiritomb with Shell Smash 0_o
I can say pretty much without a doubt that DD would make Garchomp pretty deadly, especially since it has a Megaevolution. Depending on what Gen we're dealing with here, that can decide whether or not chomp really is broken. As far as Gen V is concerned? Most likely, since there wouldn't be much to survive it's Dragon/Ground stab aside from Skarmory. Ultimately though, I think Chomp would prefer SD as it's main boosting move rather than DD as taking two turns to set up your attack generally would leave you pretty wide open for anything else in-between those turns, and chomp can't really risk that, especially in gen 6.
Spiritomb w/Shell smash:
Something that sounds really good on paper, but not so much in practice. Reason being is that just about almost every person knows to have a taunt or a phazer ready for status abusers such as Spiritomb. And even with a Shell Smash, I don't think it in particular is fast enough to really outspeed and kill anything, and the defense drop would be something to worry about. You would carry White Herb to remedy that issue, I suppose, but then your issue would be recovery. Spiritomb is reasonably bulky, so it can take a good few hits before it dies, but seeing as it now has a weakness to Fairy this time around, that's not going to help it much against things like Florges, Sylveon and co.
mmm...one thing I've been thinking about...
What if Scizor had Shift Gear?
If Palpitoad just had Earthquake...
I know all your secrets!
BECAUSE I AM THE SPYPITOAD!