It was (still is) a great system but things that would have helped.
- Use standard storage rather than proprietary, would have made expanding digital libraries cheaper/easier to invest in
- A better online store with filters
- make the downloads list usable (I don't think any of the UI devs ever had a digital catalogue of more than 5 games in their testing. It also includes all PS3 titles you have purchased in the list)
- Provide video out with Dualshock support. Easy to say in hindsight, but they kind of went down that route with Vita TV, but if you could have hooked it up to a big screen out of the box, it may have been seen more of a mainstream device.
- Could have done with slightly better ergonomics, prolonged use could be hard, but most handhelds have this problem when they are small.
All minor things, but they all add up. It is a damn shame because I would live a PS portable device now, especially if it supported PS Now, PS5 Remote Play and a good catalogue of cross/buy/play indie titles, but unfortunately I think they may have felt too burned on the Vita.