He probably would be pretty good, but 60-65m good is where I get skeptical. We're getting Christensen for free, I get that Kounde is better, but with the lack of cash and many other positions needing reinforcement it might not be wise to spend 60m on him. That unless of course he and Araujo become some kind of super pairing at CB, but it's a big gamble imo.
Fair point but I think Xavi and the club actually believe Kounde would be the best complement to Araujo.
If we look at a bigger picture and they would really form a great CB pair we could have future 4 CBs (for next 3-4 years if not more) for a combined fee of 60m or whatever we'd pay for Kounde as we've signed Garcia, Christensen and Araujo (almost) for free. Obviously we could replace Christensen or Garcia with Marmol or another Barca B player (who would also be free/cheap) as a 4th CB down the road if we'd get our starting CBs settled and also have a reliable 3rd CB.
That said, there are surely also alternatives to Kounde. I've already mentioned Piero Hincapie here a few times and I've read a few days ago Tottenham is willing to pay 40m for him. Now obviously would be a gamble as well, probably bigger than Kounde despite lower price due to less experience at the top level (has only played one season in BL) but I really like what I saw from him. He's also left footed and has even played as a LB sometimes for Bayer. If Xavi is considering using 3-4-3/3-5-2 more then I think having a leftie as that wide LCB would also be useful. Ajax's Lisandro Martinez is another option although he'll probably go to United if they'll actually sell him.
Of course Kounde is good enough technically and also athletic to potentialy cover opposing wingers if exposed 1 on 1 (and he probably would be with Alba playing high on the pitch on that side) but wouldn't be exactly using him to his strengths.
Also, about reinforcing other positions are we actually sure we would spend those 60m (if we won't sign Kounde) smarter? Would you rather pay 60m for Raphinha for example? Or assuming we sign Koulibaly for 35m and use some of that "saved" money (difference between his and Kounde's price) to pay 50m+ for Lewa and 10m for Alonso or something like that?