I get the concerns of BBZ of not wanting to disrupt a treble winning team, but at the same time, a team that has won everything is usually at risk of fatigue, lack of motivation, becoming predictable to opposition etc. You don't really have to change a winning squad, but it's imperative to diversify it. Quality reinforcements, with different profiles bring competition for places, revitalizes the squad, at the same time allows for tactical variation for the manager. A player like Pogba despite being young has more top flight experience than Kova, his physicality and athleticism are rare traits to what our cantera normally produces, whilst Kova is much of the same. Pogba a year from now will 've accumulated another year of experience in the CL, with Kova I'm not sure. Our midfield lacks strength in depth, and we 've been extremely lucky with injuries the past season. We have the Rafinha's/Roberto's, but we certainly need a third MF who has the quality and experience to fill in for either of Iniesta/Raki but also play an imp tactical role.
Let's just assume Iniesta's injured before a big match, or for an extended period at the business end of the season. Would you entrust a Busi-Raki-Pogba or a Busi-Raki-Kova? I know who I'd prefer.
That said, I don't want Pogba in an extravagant deal that also makes him our biggest earner after messi. Neither with the must-starter privileges if it were so. The rest, as a player and for the skillsets he brings, I prefer him to Kova as our next summer's signing, rather easily. And I'm not even a big fan of Pogba.