Haha, it was Black/White that almost killed the series for me. I didn't like any of the starters and found the region incredibly dull and linear. I also didn't like that they blatantly tried to recreate the magic of Kanto in the designs themselves. So many of the Unova Pokemon are conceptually ripped off of Kanto (or other popular designs).
Audino = Chansey
Conkeldurr line = Machamp line
Patrat line = Raticate line
Musharna line = Hypno line (dream eater idea)
Zebstrika line = Rapidash line (elemental horse)
Gigalith line = Golem line (trade evo rock beast)
Throh/Sawk = Hitmonlee/Hitmonchan
Swoobat line = Golbat line
Trubbish line = Muk line
Bouffalant = Taurus
Jellicent line = Tentacruel line
Amoongus line = Electrode line (Pokeball mimics)
Excadrill line = combination of Dugtrio and Sandslash.
Klinklang line - Magneton (inanimate object come to life)
Seismitoad line = Poliwrath line (tympole even starts as a tadpole)
Unfezant line = Pidgeot line (looser connection here, since regional birds are common)
Genesect = Mewtwo (genetically modified by Team 'X')
That was just off the top of my head so I'm probably missing some. Zoroark was also a clear attempt at creating a Lucario 2.0
There are Pokemon in Unova that I like the idea behind more than the actual design itself...if that makes sense? I mean Scrafty is a trouser snake so it's cool that they incorporated that into its design, but I still think it's ugly as hell. Chandelure is a perfect concept for a fire/ghost...but I just don't like how it looks. I could go on and on. :/ Volcarona falls into this as well, not that it would have mattered since you can't use it until after the Elite Four and it doesn't evolve until level 59 lol. That's actually a big problem with Unova - so many Pokemon don't evolve until level 50+. Don't know why they did that.
This was longer than I meant it to be. I really dislike Unova.