Where's the protection for the defence with Rooney as your holding player? Rooney would constantly give the ball away as well. Like he did when United desperately tried to shoe horn him into the team.
The protection for the defence comes from Gueye and Beni/Davies ahead of him. It's up to them to win the ball before it gets to our shoddy defence. I take your point but I think Rooney would work well in this setup.
When top forward players age this is the position and role they normally drop back in to. Gullit, Pirlo etc
Ultimately he would need players who work hard around him and it doesn't help our striker problem so right now I would play him up front because he's the only player with a goal in him however it would be something I would be looking at in training.
The one big way it would help the defence is they would have a short pass (a bit like when Barry done this job) instead of having to hoof it.
I'm not a huge Rooney fan and I didn't want him but right now he's the one player with a bit of creative class in the whole team at least until Sigurdsson finds his feet.