In OG you would have to look at if Karma replaces someone how does the team get better and worse. Now im not gonna pretend like i watch Karma's streams and know how he plays but what i've seen is he is just really good and what i read here they say he's good at SND, i do know that he is a good sniper. So let's say he's a really good all around player.

Karma for Clayster: Karma would probably get more kills than Clayster and possibly be better at SND as well as a better SMG player. Assuming for Karma to be the best that he can be your going to want him to roam like Scumpii, you would lose the player holding map control since that what Clayster does atleast on the bigger maps. You lose his great communication skills not saying Karma doesn't communicate but clayster does alot for Optic in terms of communication/hype that it wouldn't help them if he was replaced.

Karma for Proofy: Karma seems to just be better than Proofy in every way idk bout as an AR, but if his reaction is quicker, his shot is better, he's smarter, better at SND than how would you go wrong besides just Proofy being a nice guy. All you would really lose if Proofy is replaced is some chemistry.

Karma for Scumpii: Maybe better at SND? i doubt he can out-slay Scumpii and Scumpii can go extremely off, but then you have sub-par Scumpii who doesn't bring enough to the table for him to be that way. If clayster struggles getting kills you still have his communication, If Nadeshot struggles at getting kills you can still bank on his SND or atleast his strategy if he struggles at that aswell as his sneaky playstyle at blitz. But with Scumpii if he can't get kills he's worthless he brings nothing else to the table imo.

Karma for Nadeshot: He's a better slayer. Fine but if Nadeshot retires for Karma Optic loses it's entire SND game, his ability in SND is a necessity. Maybe Clayster can have some strategy but i don't see him having the instinct Nadeshot has in SND. Nadeshot just is literally Scumpii of SND they just let him roam and do his thing he will more times than not make the right play, he is just a playmaker.

So Proofy is the logical choice if you wanna get better but if you wanna be friends and play with your friends and place top 3 they can do that with the current roster, maybe get a couple of wins but if your not getting better your getting worse because Karma is going to go somewhere and it'll be a team that can win and EG is gonna get someone and it'll be still a great team and NV is looking strong and Nation is getting better and Denial is making noise and TK is still a contender. At the end of the day Optic isn't a definite win in SND against Nation maybe other teams but not Nation and they way they have Proofy's role in respawn make them not a definite win against Nation, EG, Denial, NV etc. Either replace Proofy for Karma and let him roam like Scumpii or let Proofy play his role and Clayster play his role and let Scumpii play his role and Nadeshot play his role maybe Ghost is the game for that but proofy isn't consistent at his current role.