Originally Posted by
Rocket Dawg
Does upgrading the derailleur system to something better make for shifting that is spot-on and reliable?
There's nothing you can get that will be more "spot-on and reliable" than a Shimano XT RD. I think your problem lies elsewhere. As roadfix suggested, maybe a bent hanger. Also, full suspension bikes are particularly prone to ghost shifting if there's any problem at all with the derailleur cable-