Unhappy, underused players tend to be most of those who move in January. Barca might have some of these, such as Pedro, Tello, Song or Montoya. Any Barca acquisitions in January may well be matched with Barca player sales. Barca might want to try a different type of forward, a DM/CB flex player, a FB/CB flex player. Add some size and strength.
Luiz is more athletic than almost anyone, and he can play multiple positions. Pep identified him as a Barca target years ago. I'm wondering if this might be Puyol's last year, he might not want to stay on given how his body is holding up.
Luiz performs both of those functions, but I do agree that we might lose someone if we gain anyone.
In my opinion, Tello and Song are expendable. Particularly if we sign Luiz, we can push Masch back into MF (where with our more direct style he would be fit better as a DM than he did during Pep's era) and Song becomes superfluous. Tello has been too inconsistent and while he didn't get that many chances between Tito and Tata, whenever he did, he failed to impress. I'd argue to Montoya hasn't quite made the cut either but he is the only player who can fill in at RB and we need him for depth atm. With Luiz though, I think he could also succeed as a RB and would allow us to have more height for at the back and give Alba more license to get forward.
I'm still on the fence with Pedro. He is a great player who is great at complementing other players and our style, plus he is clinical when he gets a chance. But with Alexis and Neymar in the squad now and Deulofeu coming back next year, his playing time will continue to be limited. I wouldn't be against necessarily selling Pedro but I'd prefer if we did it during the summer so we have time to find another forward. With Pedro out of the squad, that's when I'd support signing a Lewandowski, Aguero or Reus. But as long as he is in the squad, we really don't need anymore offensive reinforcements. With Messi back, Tata will already have enough of a selection headache and throwing another attacker into the mix will make it worse. Much like in 2008 with Rijkaard's last season, it was really hard to fit four attacking players (Eto'o, Henry, Ronaldinho and Messi) into the same formation and have it be balanced.
I just really question whether any other attacker can have the same impact as both Alexis and Pedro. Combined, both have 22 goals this season and I highly doubt any of the attackers we are being linked to could be more productive than those two, and I combine those two because buying Lukaku, Aguero, Lewandowski etc. means that Pedro and Alexis won't start due to Messi and Neymar locking down two forward positions. Considering this and our other more pressing needs that we will need to go to the market to resolve, I would like us to try and keep Pedro. Lets just splash the cash on Luiz, Ter Stegen, Reina and perhaps a defensive fullback and lock down our defense.
With Alexis, Pedro and Deulofeu competing for the third spot next season and Dongou as our traditional CF, we would have both offensive depth and tactical flexibility to run a 4-3-3 with both a false 9 and a traditional 9. What I am
not saying is that other attackers wouldn't benefit the team or saying that individually Pedro and Alexis are better than the forwards we have been linked to. But for what this team needs, we already have 85% of what we need. All Tata needs to do is figure out which players work best with one another and rotate these different connections so we are harder to predict. Alexis and Dongou are more suited to a more direct style (which is why I think Cesc should always start in the MF when Alexis starts) while Pedro, Messi and potentially Deulofeu are better with the tiki-taka approach and should play whenever we have Iniesta and Xavi.
If we can solidify our defense and have multiple attacking schemes, opponents will not be able to simply "park the bus" and will have to play more open, allowing us to play tiki-taka. That's why Tata is trying hard to get us to adopt this more direct approach because by doing that, it will eventually allow us to go back to playing tiki-taka. Its a very solid strategy, and once the team finds this balance, I'm convinced the only team that can compete with us is Bayern, (Its funny, they are going through the exact same transition that we are, just they are going from direct to possession) and since we are the OG possession team (at least in the Modern era), there is no reason why we can't beat them as well.