Currently my team is just eggies because I was breeding pokemon. Q_Q
So it's like five eggs and a Volcarona.
There isn't much re-learning as far as stats and stuff.
That's been the same since gen 2/3ish.
Also types haven't changed since gen 2 either.
Now the typing combos! Those are a bit weird and still trip me up in 5th gen. Especially bug steel and I have no idea why that is.
I wouldn't say most the designs are terrible. In fact I like a lot of the new designs. They just take a while to get use to.
At least they did for me.
http://cdn.bulbagarden.net/upload/6/6d/Spr_5b_549.png Like I love lilligant!
I think it's just awkward to get use to the new pokemon, because when you first fight them you have no idea what they are.
Plus with the new meta game and stuff it's like you have to learn things you never really needed to know back in the first few gens. XD