I'll lead by example:
Things I love:
NEOS mounting stock adjustment. Long (good leverage) lever under the turn table that positively (and securely) releases and locks for quick, one sided adjustment.
Positive locking clamps (switch action, LF switch clamps, etc).
Super thin clamp heads
Unobtrusive mounting (in my experience, 2 point has been best, but there ARE excellent 6 point mounts).
Very short string length requirement for tensioning. Some grippers are absolutely ridiculous.
Pull speed adjustment
Easy (push button) height adjustment
Wireless finger switch (instead of foot switch) [dream/not-cost effective feature]
Non-linear pull speed (very fast at low string resistance, pulls much slower when nearing tensioning, to improve accuracy)
Extremely fast sampling rate, on the order of 1/1000s. Constant re-adjustment, mimics "dropweight" smoothness
Edit: OH MY GOODNESS: MINIMAL THINGS TO CATCH STRINGS ON @#)%(*@#$@#%.
I haven't played with the Baiardo, but the ergonomic solutions sound nice
I'd spend $500-1000 on an RDC, but it really depends on business, if it's not useful data to me, I simply wouldn't buy one. To make it "worth it" to buy "just because," price would have to drop <$500.
I'd also like a networkable stringing machine where I can "capture" data from the string job (tension, overall job time, string used, frame, pattern, etc) and report out to an automated data capturing tool (for personal and customer records' purposes). This could be via a voice memo, or whatever.
If we're talking crazy: I think it'd be cool to have stringing robots, but that'd sort of put us all out of a hobby/job... This would theoretically lower labor prices if these robots weren't cost prohibitive to own, and I think this would be good for all tennis players in general. Can you imagine if labor only cost $2 and you could get your frame back within 10-20 mins [faster??]? I wouldn't even bother stringing anymore, especially if the human aspect (inconsistency) was removed from the process. I'd spend my money on strings