I'd agree with you in talent terms that he is not better than Adam Johnson
however, we have all seen that AJ's one real weakness is that he is not exactly a duracell bunny in stamina/endurance terms and, once we were 10 vs 11 that was absolutely the one quality we needed in abundance.
If it had been even stevens in number terms I agree that I would have loved to see Johnson. BUT i would have hooked Barry and played Milner centrally.
As you and others have said before, Milner is not a tricky winger.....so to compare him to SWP, Johnson, Silva even...is not comparing apples with apples IMO