I've been meaning to post something about this for awhile and kept forgetting to do it. I saw a thread on flightsim.com that reminded me, so here goes.
There have been a few hardcore helicopter enthusiasts that don't like the new easier to fly helicopter model. I think we did the right thing making the helicopters a little easier to fly (and fixing the bug with the stability problems on the JetRanger were critical as well), as more users are enjoying the helicopters than ever before. This means the popularity of helicopters in the community will go way up! That's good for everyone.
If you want to make them harder to fly (and closer to what FS9 had) then try these adjustments. I haven't tried them myself so don't complain if they aren't a magic fix for you 🙂
In the Bell's aircraft.cfg there are stability scalars in the [helicopter] section:
low_realism_stability_scale = 1,1,1
Changing these to something less than 1 will change the ease in which the helicopter flies. Around .66 should replicate FS9 behavior.