Rent? that gets a hard 'No' from me.
If it was gil it would encourage RMT, it won't affect rich players and anyone with multiple FCs on their account will be generating enough gil from their workshops to cover it hundreds of times over.

FC credits sounds better, but again botting dungeons would generate enough of these to keep multiple houses while small to medium size FCs would really struggle, especially if several people took a break at the same time.

Housing is the one system in this game that frustrates me. It's never worked 'as intended' with happy, bustling neighbourhoods. The ward system puts severe limits on outdoor items, most FCs want larger houses but they're very few in number and access to a workshop is gated behind house ownership, locking many FCs out of the content.
I supported the timer when it was proposed and I came to regret it. Let's not propose yet another band-aid that's only going to cause more problems down the line.

Housing is a system that is viable for all expansions and should provide fun for both private individuals and FCs, yet what we have is poorly planned and riddled with issues. I'd like the devs to stop slapping on band-aids, take a proper look at what players want from housing and give it a thorough overhaul, because it desperatey needs one.