I would love to see a kickstarter or something to create high quality assets for Open Arena, and add raytracing. Personally, I find that Quake 3 gameplay is more fun than any modern shooter that I've played. It's fast paced, and really well streamlined. It's just pure adrenaline.
Adding things like health regen, cover, alternate fire modes, and so on ultimately just distracts from the action in my opinion. We don't really have any more games like Quake nowadays.