I really don't think you should have to hold a button just to be able to use a weapon. I didn't find it very comfortable in DmC when doing elaborate combos (my fingers were everywhere), and I don't want to have to focus my attention on holding down a button (L2 or R2) all the time. Just pressing it once is fine.
But yeah, I agree with much of what The Final Offer said. That said, destructible environments aren't necessary - that stuff can cost a lot of processing power. Aside from that, it can also clutter up the screen and cause clipping, which can be annoying.
- I would say that a little more customization would be nice. To be able to change Dante/Nero's clothing and weapons, both in terms of shape and color. If these guys are demon hunters, I expect them to be able to work on their weapons, and to even create traps if they wanted to. It's 2014 - games should include way more RPG elements than they do right now. If you don't care about RPG elements, you can always just leave it alone.
- Also, it would be nice if environments seemed lived in, yes. Maybe we could encounter some people and do side-missions to defeat powerful demons who keep their family members hostage... I dunno. Just something small but rewarding.
- No forced character switching. I really didn't like needing to change to Dante for a few missions, then changing back to Nero. They should just make one campaign for each character. Additionally, being able to join the campaign with a second controller would be nice. I suppose Nero and Dante could fight side by side that way.
- The ability to turn lock-on on or off. Pretty sure DMC4 had different types of lock-on too, and it worked. No sudden twitchy switching between enemies.