Do you want him to play like Tata tried to? To "get the ball as little as possible"? He's at best where he plays now, immensely helping his team to create chances. His passing skills are wasted upfront. And also, his workrate is pretty meh, it's not a rare sight to see him just standing instead of moving into channels during a quick attack/counter. No, thanks, I would like Messi helping the team instead of scoring goals for his record. That's what Ronaldo does. Messi is more than that.
We would still have playmaking Messi, but more variety and dynamism in our build up.
Rakitic does an excellent job of making runs into the box and as a result (plus a few long shots) has 17 goals in 2 seasons for us - that's a great tally for a midfielder. If you've got those dynamic runs into the box from Pogba with Messi's diagonals? Game over.
But the thing I figure Pogba has over all midfielders is in transition. In games like the one against Bayern last year where everyone where we leave MSN to play by themselves up on their and fire balls up, he'd be perfect in that iteration - you could see in Real vs Juve last year how he good he was in transitioning from defense to attack.
In all honesty, that Tata quote is a bit blown out of proportion too. Getting him as little on the ball as possible then was silly because we didn't have the players to facilitate him, but at times, it definitely has some merit. I feel a lot of the time Neymar and Alba get in great positions but only look to find Messi, when using him as a decoy is the better option. Alba especially.
The biggest thing we need to work on is distance shooting; it's something we severely lacking in, especially compared to Bayern and Real. Rakitic can shoot but doesn't set himself to do so enough, Iniesta and Busi can't at all. Against Atleti our best tactic in the first leg was just shoot and let the ball spill.
You can also say Pogba's height would be a big asset, and it would be, but we've done far better than anyone expected from set pieces both offensively and defensively.
The point is, we'd have add a whole ton of dynamism and unpredictability to suit any game. Messi more than ANYONE would benefit from it.