Mate I think I disagree with almost everything you just said!
1. There's many reasons for us to sign him, lack of quality in the position even with fully fit squad and lack of other long-term players in the same position we can realistically buy to name a couple.
2. AVB clearly wants to take Chelsea into a new direction, out of the stone-age, Lampard being very much a part of the dated Chelsea team. United still play relatively dated which Lampard is used to. He may be a legend but I think AVB would sell him if it were up to him, perhaps not to us though.
3. I think if the price/wages are right we would buy him despite his age, although it's debatable. I think it's extremely harsh to say he wouldn't add anything to the team too.
4. Why do we need energetic midfielder's who can burst forward? We need a midfielder who is class enough to attack through the middle and the vision to play a defence breaking pass onto the strikers, Lampard isn't exactly bad at that is he?
I'm fairly certain this transfer won't happen either, but I don't particularly agree with your reasoning.