i agree that unown should stay as what it is, a gimmick BUT i would like to see them develop the lore around it a little more. I know there's an explaination for the unown in the movies but not in the main games so i would like to see that more explored (HGSS missed the chance to do this). Spinda, now that i think about it should also stay as the pokemon that's never the same. Pinsir, kangaskhan, mawile and medicham all recieved great boosts with megas but there's one pokemon who everyone seem to want a mega or a regular evolution for i but GF doesn't acknowledge it which is dunsparce. It might not be as weak as the ones i previously mentioned but more in the level of charizard, absol or banette. It has a nifty use but it's weak and really screams for something. it's HP is great at 100 and with access to a bunch of moves with secondary effects it could become more defensive with a slight increase to attack and remaining slow. gaining ground as the secondary type would make sense if it retained his underground dwelling nature. It could however gain dragon typing (i know dragons overload) but it can fit if it gains a more dragony look (like the treasure protecting cave dweller dragon). Keep serene grace, put it's stats at
100/100/105/65/100/45.
When you think about it, zygarde is the indirect ultra evolution of dunsparce, just like diancie is for carbink and alomomola is for luvdisk. They look similar but they are way superior.