Zigzagoon/Wurmple. Pretty much just Rattata/Caterpie/Weedle all over again.
Lotad's family. Christ, there are no words.
Surskit. Another Bug Pokemon for the pile.
Shedinja. Cool gimmick, rendered useless by the fact that he's weak against Flying, Rock, Fire, Ghost, and Dark, and the chances of any given Pokemon
not having one of those types of attacks is pretty slim. And aside from his Attack stat, he doesn't have high enough stats to off-set the 1 HP gimmick.
Plusle and Minun, just trying to cash in on the cute popularity of Pikachu.
Volbeat and Illumise. Look, even more bugs.
The Gulpin family. Fuck those Grimer wannabes, Grimer was already pretty pathetic back in the first Gen.
Torkoal. Only really good if you want a brick wall for your opponents to bash themselves against.
Spinda. The most 'normal' of all Normal-type Pokemon, with it's 60-base stat for every stat.
Chimecho. Doesn't have terrible base stats, but it has a pretty terrible move-set.
Luvdisc.
And the fucking Regis, which are the three most useless Legendary Pokemon I've ever seen, considering how hard they are to get in the first place.