I guess not all Rebels are alike. I have owned four, '85,'99,'04, and '16, and they have all been the easiest shifting bikes to shift I've ever ridden, out of well over 50 total. They click into gear while running quietly and without the loud CLUNK most bikes make, and the shifter is like a hot knife through butter. The shifter linkage could be adjusted wrong, the clutch could be adjusted wrong, or dragging for some other reason. I did have a couple of bikes I had shifting problems with where I found the friction plates were warped, and the clutch was not releasing completely. Could also be a problem with the internal shift linkage or drum. But by design, the Rebel seems to be an excellent shifting bike.
I typically do not put bikes into neutral except while letting them warm up before taking off. I keep them in first and hold the clutch in at stop lights, and also park them in first. But before I posted this, I started my Rebel up, warmed it up for 5 minutes, then shifted it up and down through the gears. I found neutral first time every time. Also be aware that if an engine is really hot, a wet clutch may not disengage as well. I've had a few bikes where the adjustment at the lever would change noticeably when the engine got really warm, and shifting would become notchy.