I used to hand-fly raw data ILSs on the 319/320/321 on a regular basis, and I remember that -even in smooth air- some aircraft used to slowly but surely pitch up when left untouched, even though with no input on the sidestick the FBW should have theoretically maintained a constant one-G flightpath. Most noticeable when clean and quite annoying.
As far as the displayed aircraft track not quite matching the ILS QFU (final approach track), this was also common and a bit annoying, but for whatever it's worth I see it happening on the B744 as well. I suppose the track information comes from the ADIRUs/IRUs and of course after some hours of flying some errors are introduced...
Still beats letting the autopilot fly!
