I don't remember this has been mentioned.

So, why weren't the bikes transfered over from MKWii?

Hideki Konno told Nintendo Power that the only reason bikes were included in Wii was because of how much fun it felt to do wheelies with the Wii Wheel, and he went on to say that with MK7 their goal was to focus on making the kart control even better than MKWii, thus they didn't have time to put in the bikes.

I do like mario kart 7 a lot, and more than mario kart wii...

but lack of time, isn't really a good excuse... being mario kart's essentially been similar and looked the same as the the gamecube version released years ago.

I'd argue, that the bikes were gimicky (like I thought the whole wii version was) and unnecessary. But that's me.

MK i though you were talking about Mortal Kombat (O_O).

Why is the feather only in MK1? Why didn't we have two drivers in Mario Kart Wii? Where did the fake "?" Weapon go?

When it comes to Mario Kart, I learned to stop asking "why" and just have fun.

You're not a serious gamer.

I used the bikes in MKWii once- regretted it :( No idea why they're so popular

Bikes in MKWii were good. This time they have focused more on getting Kart handling right, in fact I think MK7 has the best and most balanced selection of Karts ever. Adding bikes and making them as much balanced, would have taken them too much time and they wanted the game to come out for holydays.