As far as I am aware Downing and Mata both play primarily on the left. Are you sure about the fact he plays on the right? Check that out. I think you are mistaken. Not sure though.
Young and Downing interchanged alot last year and started to develop a good partnership by the end of the season. So right is possible.
One thing we forget about our 2nd place finish in 2009 is that we had a genuine left sided player in Riera and whilst not brilliant he provided good width and maintained posession really well. Th gamble on foreign players(non epl) requires patience and time and we have little of both. It's so important to start the season well, personally I feel that will only be achieved through solid reliable signings rather than flashy hopeful signings. Apart from Suarez most foreign young talanted players have taken at least a full season to flourish in the prem. Ronaldo, Nani, Pires, Nasri, Modric, to name a few. A Mata would be great if complimented by the signing of a Downing.
Finally I feel we may have dodged a bullit with Wickham, as good as he looks for Ipswich I do not feel at his current age that competing for a berth at anfield would be good for him or us. He didn't make the u21s first team yet will now be first choice at Sunderland? I will watch with interest. Ngog was sensational in the reserves and for the french U21s.