Pokemon I found disappointing:
Blitzle & Zebstrika
A Zebra Pokemon was something I always wanted but unfortunately it didn't live up to my expectations. Blitzle's defenses are so low it falls easily so guys, if you are training one please give it an Exp. Share. After evolving, Zebstrika's defenses are finally patched up but a lack of good moves was bad. Mine was able to beat Elesa's whole team though cos I did an Attract + Shock Wave + Flame Charge strategy. At least the design is awesome.
Purrloin & Liepard
Its defenses are so frail and all its stats suck apart from Speed. Also, it starts out really weak offense-wise and takes way too long to learn Night Slash. Definitely the worst of the cat Pokemon IMO.
Trubbish & Garbodor
These Poison-types really stink, don't use them. They are physical-based but the problem is the only physical STAB move they learn is Gunk Shot which is so inaccurate. And the Garbodor with Weak Armor are even worse. Hate Garbodor...
Foongus & Amoonguss
These Pokemon are so crap, they are really sluggish and their attacks don't do much. I didn't really enjoy them a lot cos of that.
Stunfisk
One word, derp. Very slow and its like a terrible novelty Pokemon.
Heatmor
Definitely the worst of the Unova Fire-types.
Klink, Klang & Klinklang
I love these gears, they were OK. The problem is they are physical attackers and they don't have the right movepool to pull it off.
Pidove, Tranquill & Unfezant
I love the design, but the movepool is terrible. Physical based but the only physical Flying-type attacks they can learn are Fly, Pluck and Aerial Ace. I still enjoyed using Air Cutter/Air Slash on a Super Luck Unfezant equipped with Scope Lens. If you want to use this pigeon, get Super Luck for the ability cos Big Pecks is terrible.
Cryogonal
I love the design but its defense is so terrible despite being a special wall. It's like an Ice-type Blissey in some way. At least it gets an interesting movepool though.
Druddigon
One word, terrible Speed. Good movepool and abilities make up for it though.
Shelmet & Accelgor
They are very interesting but their strategies are so different. Shelmet uses defensive tactics but when it evolves, it has to adapt to being offensive. Accelgor's defenses and movepool sucked despite the cool design.
Karrablast & Escavalier
Cool designs but Escavalier's real dilemma is Speed. So sluggish everything will attack before it unless if it's Munchlax or Shuckle. Like Accelgor, Escavalier's movepool also didn't live up to expectations.
Alomomola
I like it's amazing support movepool but on the offensive spectrum, it's physical-based but lacks good physical Water-type attacks. Just focus on its support moves and you should be fine.
Woobat & Swoobat
The design looks cute and quirky but their stats all stink apart from Speed. At least they can learn Acrobatics, which is nice.
Darmanitan (Zen Mode)
I hate it cos when Zen Mode triggers, you are so close to getting knocked out which is bad considering Zen Mode slows Darmanitan down and turns it into a Special attacker. Sheer Force is the much better ability.