Look, I'm not the biggest dephh believer. In fact, I think his calling is not as strong as other IGLs in NA.
However, I think it's stupid to believe making Sacy IGL would improve SEN's performance at all.
Sacy is not IGL material, he and pAncada were clueless throughout their first appearance on split, while dephh was the only one making strats. He's a good midrounder, don't get me wrong, and he could definitely study up on set plays and enemy team strategies and learn to become an IGL at some point--but as he is right now he would not be able to take up that mantle for a while.
In my opinion, there is nobody currently available in NA that would be a worthwhile replacement for dephh as it is. That is not to say he's the best IGL Sentinels could have, just the best of the rest.
-FNS is not going to leave NRG anytime soon
-I'm iffy on stellar and 100T in general, their discipline has looked rusty every since sean gares left.
-vanity calls too much on feeling to be an S-tier IGL in 2023.
Personally, I believe Valyn and Steel are both vastly better than dephh as IGLs, but:
-Valyn primarily plays smokes, and I'm not even going to bother explaining why adding yet another smokes player to the roster with pancada in it is a bad idea, and while he can flex, I don't think he'd be as comfortable on other roles quickly enough to give repeat his star individual performances thus far.
-While Steel is an S-tier IGL, he has huge issues with team chemistry, and his style of leading is so specific and uncooperative with anyone else's vision that, either the roster has to be up to him, or everyone has to adapt to his style of play--which might create issues for players with opinionated ideas of how to play like Sacy, and create friction between him and Sykko.
Dephh isn't even that bad, he's just mid by international standards. He's top 4 IGLs NA, putting side the huge gap between 3rd, 2nd, and 1st place.
So long as he studies a lot more with the meta that's been developing (and will develop now that Gekko's out), then his calling will be adequate enough to set up his star roster to success, maybe not to NRG levels, but success nonetheless.
I predict Sentinels to be top 3 in the Americas league after a year or so.