I think we can make do with Rooney as the sole striker. Put Depay, Herrera and Mata behind him and they'll create enough. Although Pedro still may a chance of coming so he'll slot in somewhere up front.
Defence is a completely different issue though. I'd say give Jones one of the Centre back spots and keep him there, probably with Blind although I'd prefer Smalling. If De Gea leaves at least we've got Romero who is decent.
Overall though I think this side is better than last season's.
Rooney certainly is a wonderful striker, but what happens if he gets injured? You used to have RVP and Falcao as bona fide strikers to call upon, but now you only have James Wilson.
Pedro is capable of playing as a forward so perhaps he can be a replacement, but I think he's much more of a winger.
You have options in defence, it's just the quality that's the issue. Jones and Smalling IMO aren't that great, plus you are losing a lot of quality when De Gea is gone. He virtually saved LVG's job.
That's not to say we don't have our own issues too. We have too many strikers on the books, Rodgers is a bit too friendly with Lovren and Skrtel, we probably need another fullback, and for some reason Rodgers is oblivious to the need of a DM. Maybe he has some kind of high-pressing game plan that negates the need of a DM, but I'm nervous.
