Currently /c roll bluff check does not really work as people instantly OOC know you are bluffing and become hyper aware of what you are doing.
So my suggestion is to add a part of your bluff skill to the visible (yellow text that pops up) part of all or fitting check rolls.
For example.
10 str 0 bluff = "X's strength is average"
10 str 20 bluff= "X's strength is impressive"
Etc
That way you can really use bluff in a flexible way.
Maybe add a toggle to turn in on/off.
I do agree that as-is /c rolling bluff checks exists mostly as a gag
Maybe add a /c bluff command that works like how the pickpocket function works. For example, a pc is lying so they type /c bluff; Any Dm would be able to see it, and anyone in a proximity would be forced to make a hidden roll against the liar's bluff skill as a dc. If anyone passes that dc, they get a notification that feel what may have been said is false.
Roll to save could be: 1d20 + WIS x lvl/2 + Int mod