Yes, turning becomes harder and if you're not snappy enough with your bike yet, getting through pedestrians at low speed is definitely more challenging. However, the pay off is getting up to and maintaining speed and absorbing bumps.

Sticking with 27.5 is fine. MTBs used to be 26, then 29ers came out, then 27.5 came out as an in between of speed and smoothness of 29, but agility of 26. I have both and prefer my 29er for commuting and light trailing/cross trail, and prefer 27.5 everything else. I used to commute 27.5, but had a lot of uphill and funky obstacles and shortcut sections over around 32 min trip. Once I moved to a flatter and more open town, I switched to 29 for the cruising. They are faster, but more of a handful.