As a aerobatic/3D pilot I do try and get things as close to center as possible. I've never tried to change incidence but have tinkered with thrust angles. I also try and get the elev neutral with CG. 25 yeas ago it was much easier as the stuff I built was straighter than most ARFs. I had a 50cc AW Extra once that I could not get the elev halves to zero out with each other. I leveled the fuse and put a Robart incidence meter on each one and was going to have to drill out the rotation pin and reset it to get it right. AW had great customer service and mailed me a pair that matched up. On that plane the stabs were on a small wing tube so it was pretty easy.
I'm getting off topic but yes it's a problem. I've also noticed on a lot of ARFs that they twist the control surfaces when heating the covering and that has to be fixed. It's a little extra work to get things right but makes for a MUCH better flying plane. I don't think a lot of guys realize they are making correction in flight that they would not have to do if the plane was right.
David