OK so people now make petition to Tim Sweeney to make UT4. Right.
If anything the singleplayer Unreal should be revived, with multiplayer in it of course too but do not "just" focus on the multiplayer. We don't need another "trainwreck".
I can perfectly imagine a true Unreal 3 perhaps even still on the latest uengine 3(unreal 3 on uengine 4 would be weird).
There can be enough innovation and ideas, it's all there. A game that would be throwback to all the fun and exploration and raise the bar a little more. But that most likely won't happen. Unless I would get in charge of the project. Though I am a bad leader but at least I have specific ideas and I know what would work in this case. Masses wouldn't be necesarily targetted, what would matter more is the quality of art and gameplay. Not to make all easy shallow game. That's a never ending circle and mistake so many were making. The players should try to learn new and adapt to the game. Not that the game will adapt all to them and they can just sit through it and crunch on popcorn. Have some real thrill please. Make them scarred for life from the game. Get harder.
Then for those who scream for another Unreal on Na Pali, why not make a sort of semi MMO on ue4 which takes place on Na Pali after the events of original and have players assume various races and battle it out in a war that would ensue. And add all the original unreal locations to it too so players can drool in nostalgia while it's also next gen and they all have the familiar feeling plus new...
And what about the loose ends? Make strtegy game based on Unreal 2 strider wars.
And then as final step....
Unreal 4 and then nothing...because Unreal 4 would fucking bring end to everything. It would be the biggest and ultimate conclusion to all. Various characters could be even brought back to join the "forces". That sounds a bit silly but trust me, it could work, especially if you would be thinking of the same thing.