I hope we sign skilled players who are also athletes.
Tbf, although Barry may be slow, he covers better than just about everybody else in the Prem who plays that position because he reads the game & he's willing to put the hard yards in & bust a gut to get into position (something Yaya won't do). He can do the required job in the right system.
In the Premier League we can sometimes get away with Yaya + 1 anyhow, but in Europe it's not on. We probably need two plus Yaya or even 3.
The bigger question imo is whether Mancini will learn from watching how Dortmund & Bayern have packed players into that area against strong teams & squeezed them out, or whether, again, we will leave holes in the midfield & get battered out of Europe.
Garcia & Rodwell could both do the kind of job Martinez does for Bayern IF they had the players covering around them. Martinez is very slow & can't run a lot without getting tired. Bayern give him a simple job to do & cover the rest with other players.
For us to do that, someone else would have to cover for Yaya, because he sometimes won't do it & that's when the system will fail.
Leave Martinez on his own with 2 or 3 players running at him (like Barry or Garcia sometimes have to cope with) & he's fucked as he's too slow to catch them (he even had to rugby tackle a Barca player in the middle of a packed midfield on one occasion). Yaya often leaves a hole & it needs two or 3 players at least to cope with the kind of packed central mid areas Bayern & Dortmund will use.
Other teams will learn from that & evolve, so there are likely to be more teams potentially causing the same problem.
I hope Mancini works hard on it, whoever we sign.