You just forgot to mention how Cesc never started any big game for Barca in the midfield in 3 years (except for the last game against Athleti) even was he was more in form than Xavi, the coaches always preferred the tried & tested Xaviesta combo come big games. For the NT, he's played well in almost every match he participated in agains the oppositions that could be considered as one of the best there are out there.
For the NT there are games where he scores or assists. Again, I don't remember him impacting a game overall the way a more complete midfielder would. Sure he may be more decisive than Koke with that output (often against cannon fodder and extremely inconsistently) but by that logic Ronaldo is better than Messi just cause of a goal output that's more decisive (try not to start a huge discussion about this, it's merely an example).
Also, bringing up the 4 man midfield games doesn't point in Cesc's favor. It's just a clear example of how Cesc is a complete passenger in buildup while our other midfielders (Xavi and Iniesta) dominate our passing play. For Spain and Barca, he's never taken on any role other than providing a decisive pass or finish, showing that he's limited to useful actions only in the final third. And it's not just cause he's an attacking midfielder, cause so are Silva/Iniesta and those two still manage to provide a lot more to Spain's overall game cause they aren't limited players.
Sure his stats are impressive but when have you seen Cesc really influence overall buildup and support the team? You can't really do that if your only claim to fame is some goals and assists that are often padded stats. Koke on the other hand is a midfield engine helping out an enormous amount in all areas (defense, buildup, and attack). His influence extends beyond goal/assist numbers the way the best midfielders (Xavi, Iniesta, Busi, etc.) have.
The funny thing too is when people talk out about the defensive part of his game, when he actually participates more than both Xavi & Iniesta in that aspect who both barely try to defend. He also covers more ground on the pitch.
The point was about Koke doing more than Cesc. You couldn't possibly make a claim for Cesc>Koke defensively if you tried as that's nonsense.
Anyway I'm not sure about selling him as our squad is thin enough as it is, but his stats don't fool me. He's a decisive player but I'd NEVER want to build a team around him long term in midfield. He's simply too incomplete and our entire game would suffer because of it.