Male Combee. :| It could easily have carried on the "living honeycomb" theme and evolved into an even bigger cluster of bees, which would still be weaker and less desirable than Vespiquen without being Magikarp-tier like Combee is. Argh...
I suppose it's only fair to give one to male Salandit as well, (although that Pokemon doesn't have it nearly as bad as Combee) - maybe a handsome, princely lizard with low Attack/Sp. Attack stats and a lot of support moves like Helping Hand or Baton Pass? It could even have a signature move or ability that benefits Salazzle specifically - like, powering up all Poison and Fire attacks by female Pokemon, or something?
Pyukumuku, just to drop the "no attacking moves" gimmick. >_<
I always thought Stantler could use an evolution that expands on its spooky, hallucinatory theme.
Cryogonal needs an evo, a pre-evo, different forms - anything. It has such a strange and fascinating concept - a sentient being made of water molecules that can freeze into a solid, battle-ready form - and it's a shame that nothing was done with it beyond "single weird-looking snowflake forever".
Finally...A Mimikyu evo where it's wearing a Raichu costume. :D