Hi VikingRC2,
Thank you for posting your question to this Apple (user-to-user) Community!
Re: "How do I reverse a video clip on the iPad?"
Am no expert in this area, yet your question deserves some response, if only to get your discussion underway.
Doesn't seem to be a way to reverse a video clip in either iMovie: iMovie User Guide for iPad - Apple Support
or
In Apple's free Clips app from the App Store: Clips User Guide - Apple Support
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Seems it may take a Mac to reverse a video-clip. ?
("Final Cut Pro" is Apple's professional post-production software available at a price, from the App Store)
Reverse or rewind clips in Final Cut Pro for Mac - Apple Support
There is a version of "Final Cut Pro" for iPad. I didn't find any info. in that how to reverse a video-clip.:
Someone who is using the software may know better.
Here's the: Final Cut Pro User Guide for iPad - Apple Support
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Re: "If not native to my system, would a new iPad give me more editing features?"
Seems the editing features are within the software, and current versions may or may not be updated with new features. You could send a feature request to Apple through their feedback website if you wish.
All the best :-)