Ok so this is all reasonable logical speculation and some confirmed factoids, i dont have all the links, anyone who might want to add is welcome.
So, here is what i believe what Saadhak is cooking:
What's Confirmed
He wants a Flexible Team
He wants a different coach
He doesnt want another Aspas
Why did he reject certain Prospects?
GuhRVN
Although he is a bread and butter Controller, he did not shine during The Union's run on Ascension.
He is good as a Controller, but he might not be as good of a teamplayer that saadhak may want, saadhak clearly looks for cooperative playing styles, not individualistic, we can tell by the fact "LOUD Highlights" usually happen when the enemy team plays like bots (walks in one by one) or when the play fell apart and its left for one player to truly solve the round.
Loud constantly plays as a team, trading, midrounding, faking, antistrating, with flashes of individual briliance, but they dont play into the puggy (Play of the Game) style.
GuhRVN also is a Controller ONLY player, and Loud just lost their star duelist. Picking up Guh would mean that Tuyz would be locked into the Duelist role.
Tuyz is a more reserved duelist and this would lock Louds playstyle to a more passive game.
Xand
While Xand has played as both a flex player and a duelist, his agent roles dabbled between Initiator, Duelist and Chamber. We know from his gamestyle that he is a very aggressive player, but another thing that most people seem to overlook is that he was also an IGL for a while, why is this relevant? well, because Xand is Confident, and Confidence left unchecked turns into arrogance. The chances of ideas clashing between Saadhak , Less and Xand are far too high. A frustrating Series could cause a rift worse than Aspas/Less.
LOUD already has two initiator players, a third could cause conflicts since the only person that could switch with Xand if his entry didnt work would be Saadhak himself since Neither Xand nor Saadhak have been shown to play the Controller Role optimally, say what you will about Tuyz, his Ability Usage is great along with his ability timing.
This means Xand would lock the playstyle into more of an agressive one.
Havoc
Havoc falls under a similar predicament to Xand, however he becomes a worse prospect due to his international inexperience and that he would need to be trained INTO the LOUD system, which would mean that Saadhak would need to IGL AND COACH all 4 players at different stages of their progress, Less is becoming an IGL, Tuyz and Cauanzin are only now becoming semi veterans. while Havoc would be the fresh newbie. There is no guarantee he would be able to perform too, since his mental would also need to be trained, a frustrating series to a young player could break their mental for the split or worse the season. with how much Saadhak would have on his plate it would simply not be a good risk to take. Same as Xand, aggressive Style, Havoc would need to be "tamed".
Then why QCK?
QcK has been playing for a long time now and has been to SEVERAL International events, he has played both as a Controller and a Duelist, he has the aim and is aggressive.
However, linking back to that factoid that Saadhak wants a flexible team, we can see what he is planning. Tuyz has a more reserved Playstyle, he is a trader, not an entry, while Qck is a entry and less of a trader.
With Qck, Saadhak can have bothe playstyles he might want with certain comps.
He gets a more group-oriented Duelist AND a more Individal Duelist, while BOTH can play good Controllers.
QcK can play greatly with agressive duelist like Raze and Jett
While Tuyz can play with more mental Duelists like Phoenix and Yoru
all of this without having t5o worry about mental since Qck has already been battle worn, as well as Tuyz.
Loud has gotten more room to cook up meta comps because they know have all agents covered, while before they were restricted to raze and jett they can dabble into Neon, Yoru, Chamber, Phoenix, Sage, and other niche picks that they couldnt before due to Aspas not being comfortable on such agents.
To summarize and > TLDR
QcK and Tuyz can swap roles easily.
Both have strong mentals and international experience.
Saadhak gets an introverted Duelist and an extroverted Duelist
Saadhak gets a cooperative Controller and a individualistic (Clutch) Controller
Saadhak can experiment with more niche picks like Yoru
Saadhak can change up the entire rythim and playstyle with who plays duelist
making opposing teams having to worry about double the comp possibilites for a map.
Loud becomes harder to predict against and antistrat.
The Map pool can be even bigger due to different playstyles.
Saadhak is cooking and im smelling a full on GOURMET BUFFET