I think a lot of reviews are fairly satisfied with the 3's handling right now with one of the main complaints, if any, being the relatively sluggish straight-line speed and lack of power.
That said, I think there will be plenty who will be happy to drive a Mazda 3 that handles as well as it did before, but has more power and is faster. I know I would be. I thought the Mazda 3 loaner I had a while back was a ton of fun, but I admittedly don't know if my senses have been dulled from driving a CX-9 for so long now such that anything smaller and shorter would seem very responsive and capable in the handling department.
Torque steer and TCS are certainly worthy concerns though, but some consider the former to be even a charming character flaw. That's what I read in some of the comments at Jalopnik on the articles that discussed the new turbo Mazda 3 anyway, with many referring to the MazdaSpeed 3's torque steer.
I know I'll at least test drive the new turbo Mazda 3, but I wouldn't say I'm committed to getting one just yet when my CX-9 lease ends.