For me, I really am not a fan of Patrat/Watchog. I love Lillipup and Herdier, but I don't think that Stoutland was necessary, so I'm not a big fan of it.
I don't like the elemental monkeys, but I'm not a fan of monkeys in general.
I wasn't too thrilled with Pidove and it's evolutions.
Not a big fan of Darumaka/Darmanitan either.
I could have done without Garbodor, but it's not the worst Pokemon ever created.
Other than that I really loved most of the Gen V Pokemon.