Shit really, I didn't realize that.
Its not so much the straight swap deal between the 2 that bothers me it's when people are talking about adding £15m along with Rooney (who's worth between 30-35m easily) making Mata's value reach around the £50m mark. Not a fecking chance he's worth anywhere near that figure.
If you did, perhaps you shouldnt add a "Rooney isnt shit" in every post of yours as it makes little sense.
Regarding your point, transfer fees are dependent on quite a few factors. Simply saying Rooney's worth 35mil but Mata isnt worth 50mil doesnt mean anything. It all depends on the needs of the buyer. Someone like Real would pay 35mil for Rooney as they need top quality upfront, doubt they'd pay even 35mil for Mata considering they already have Ozil. Similarly, a club like Monaco/PSG would value a player of Mata's ilk more than Rooney as they have genuine top quality upfront already. Or say a Liverpool if Suarez didnt want to leave.
A 15mil+Rooney deal for Mata wouldnt make sense for us though, that I agree with. With his head in the right place, he's worth more than Mata for us given we already have someone like Kagawa in the team.