Is it normal for my tool changes to get flaky after a few hundred prints?

That dock issue sounds like the usual slow drift that shows up on these after a few hundred changes. On mine it turned out to be a bit of filament dust and a tiny blob of purged material built up in the dock pocket, so the tool wasn't seating all the way home. It would still print fine after a nudge, exactly like you describe, becuase the tool was close enough but not fully locked in. Take the docks off, clean them out, check for any wear or play in the latch, and re-check the screws while you're in there. The dock alignment procedure in the handbook is the one to run after that, and it only takes a few minutes per dock. If it keeps happening after a clean and realign, then look at the selector position or a slightly bent pin on the tool, but nine times out of ten it's just grime or a screw that's backed off a hair. On the waste side, yeah, that's just how tool changers work. Every swap purges the old material out of the nozzle before the next colour starts, so a long multicolour job with lots of layers is going to chew through filament no matter what. What helps is printing more copies of the same part at once, since you spread those swaps across more parts, and arranging parts so colours change less often between layers. There are slicer settings that trim how much gets purged, like flushing volumes per filament, and you can ussually shave a bit off if your colours aren't super contrasting, but go easy on it or you get ghosting where the old colour bleeds into the new one. Dark to light transitions are the ones that punish you if you cut it too thin.

I wouldn't panic about anything wearing out yet. A couple of odd fails after a few hundred prints is normal, and a clean plus a realign usually sorts it. Mine's been doing long PLA and PETG jobs since spring and apart from that one cleaning session it's been hands off.

Ha, this takes me back to the days of bowden setups and manual filament swaps mid-print, standing there with scissors waiting for the beep. We've come a long way. One thing I'd add is keep an eye on the nozzle wipe area too, mine collects little shavings that eventually mess with the homing if I forget about it. As for the purge waste, I just toss the blobs in a drawer and when I've got a pile of same-colour chunks I melt them down in a silicone mold for various pointless desk trinkets. Not efficient but the kids love it. How many hours you got on the machine so far?

Mine did the same thing after a few months and it turned out the tool changing got noticeably better once I stopped printing directly off a fresh spool. Cheap filament has more diameter wobble than you'd think, and the extra friction seemed to make the swaps sluggish. Switched to a spool that fed smoother and the stalls basially stopped. On the waste front I keep a jar of the purged bits by the printer and use them as test pieces for new settings before committing a big job, so at least it gets used for something.