Well, you know, Spinda's pretty much entirely a gimmick Pok?mon with the "hey each one has a different pattern" thing going on, so I can't say it's likely that they'll give it more attention than that :V
A Spinda evolution would be fine indeed, especially if they give it more moves to use with Contrary. Superpower is all well and good, but imagine it with a Ghost-type varient that boost Sp. Attack and Sp. Defense. Now that would be something special... er, no pun intended.
While we're making wishlists, I'd like to see evolutions not only for the weaker Pokemon, but for guys like Pinsir, Torkoal or Carnivine as well. Y'know, guys who have the right stats, just the wrong distribution or typing - giving them a new form that's more competitive and unique (Bug/Ground, Fire/Steel, Grass/Ghost?) would really give them a new lease on life, I think.
Other than that, my list isn't too long: Farfetch'd, Girafarig, Dunsparce, Qwilfish, Corsola, Delibird, Sableye, Mawile, Banette, Pachirisu. Give them a stat boost that brings them up to par with the other post-gen evolutions and I'll be content. A Dragon-type Eevee would be nice, too.
But it could have been so much more if it weren't for those terrible stats.If it only sapped when switching in and sapped 6% and recovered 6% relatively it wouldn't be that broken. Also grass type immunity and rapid spin would work against it. Phasing wouldn't that much of a problem as 6% isn't that much of a heal, but I wouldn't know the usefulness in double battles. The only thing I would see wrong would be something like parasect having black sludge, dry skin in rain and a move like that giving it a load of recovery against anything not fire.
Parasect becoming not only viable, but
overpowered would be well worth the price of admission in my opinion.
Though so long as Grass-types remove it on entry like Poison-types do with Toxic Spikes and do away with the classic version of Leech Seed to keep Stall teams from leeching people dry, you could probably go as far as a 12.5% drain without worry.
Stealth Rock is a huge pain in the ass though. I was kinda hoping that Gamefreak was cutting it off at the legs by removing the TM in the generations going forward, but they had to go and make it a Move Tutor again in BW2. Love it or hate it, I guess it's here to stay. :derp: Cutting its effectiveness in half would be appreciated however.