Well we won't run out of pairs in SIF until this summer (Either June or July I can't remember) so I feel like KLab will at least wrap up the pairs before we do anything else. But after the pairs are wrapped up, it's a mystery to what will happen next! I have no real preference over what happens to Aquors but I'll put the pros and cons of Aquors apps.
Aquors added to SIF
Pros:
Less apps means more phone storage. For just EN players this shouldn't be an issue, but for EN + JP players it would be a hassle to have four SIF apps.
Loveca convenience. Instead of buying two iTunes cards for loveca you can have it all on one account.
SIF is continued on!
Cons:
Aquors will have more attention than Muse. Aquors is going to have a shit ton of songs like Muse and once Muse members run out of pairs it will probably revert to just Aquors members.
Clusterfucks of cards. This could mean new N cards as well for Sunshine minor characters.
Aquors only game
Pros:
KLab brings in more money. Two separate apps means more players spending more money for loveca.
Muse and Aquors are balanced.
More cards. I know I love N cards and seeing new ones would make my day. Idk if is just a personal one.
More songs. Not only will you have more songs to choose from, but you can play a ton with multiple servers.
Another JP server! All of the nice JP updates can be on two apps or more if EN/TW/KR come out the same time as JP.
This isn't a point, but there hasn't been a single card of any of the Aquors members. SIF always makes at least promo cards for buying merch or to advertise the anime. KLab would have added cards by now.
Cons:
A lot of apps. Same as the reason above.
SIF would still, probably be pushed aside.
More money spent of love gems. Same as the reason above.