The F30 generation 3 series rides slightly higher than the prior gen E90's, and on top of all of that, they now incorporate electric steering instead of the old hydraulic steering found in BMW's for pretty much ever. This gives off an impression of a less sporty car and more akin to a luxury vehicle - BMW has always been in the "luxury" marketplace, but was always seen as the performance machine to aspire to.
The enthusiast BMW owner is one who looks for the sporty ride and aggressiveness to the vehicle - the new 3 series takes a little bit of that edge away in favor of trying to cater to the larger masses of people who simply buy the BMW for the name and prestige. I'd almost garner to say that the average owner of a 3 series owns a 328i off the lot, and they're probably a 40-something female looking for a "nice" car. But definitely yes, the F30 drives a little softer than the E90 does.
Owning both at the same time (I have an F30, my wife drives an E90), I can't honestly say I like one over the other. The F30 is slightly larger too, which does affect some handling, but honestly speaking, I don't really notice any difference in either car taking turns at high speed. Both are very well planted through turns, have crisp response, and are fantastic to drive. There are days I hate the electric steering and it's lack of heft, and there are days I hate the hydraulic steering and how damn heavy it can be at times. Pro tip - get rid of the run flats on the F30, and it feels SO much better too.