Should never have signed Rooney, end of.
With him being the big name + big wage player, Koeman will probably not be given much choice but to have him on the teamsheet each week - apparently not having him there against Sunderland caused problems (If media idiots are to be believed)
If anything, it's Koeman that needs to man up, and tell Rooney to either keep up front, or get dropped (And stand up to the board if there is pressure from them). Instead we seem to choosing the squad around Rooney, and it's not working
Actually Rooney's performance was not bad in every matches, many other players are underperform than him.
The poor performance of our team is come from the formation, the selection of the players (very important), the possession, all these reasons are come from the RK's decisions, end of.