the 35 f1.8 is only 7mm longer than the FE 50 f1.8, and 300g (little over a hundred grams more).
It's completely reasonable in size.
the 28-70 will be massive, like 1000g territory I bet, however, many folks will be ok with that. It wasnt too long ago that people were shooting with the 24-70 mk1, which is probably enough tougher to use due to the extreme length and backward zoom style.
3 of the 4 announced lenses are enough to flip a bunch of Sony shooters I'm sure.
At minimum, these lenses are so compelling, it will be worth it to try out the system. Personally, I think I'm over it after sleeping over it, it's a great release by Canon, one of the most exciting releases aside from the 5Dii
It's very nice, but not for me at this point, and if this drives Sony prices lower, even better, I could really use another gen 3 body 
At the very least maybe it will push Sony to give us a 35 f2 lol.
I made my bed with sony years ago so G.A.S. might talk but I've been really happy with Sony as a camera company and their camera and lenses do everything I need.
The thing about Sony is that they are hyperattuned to both their competitors and their customers. I suspect that the MKIII bodies still outperform canikons best efforts...but sony doesn't like others casting a shade on their hype train lol and we still see some nice releases from Sony over the next couple of months.
when it comes out.






