The problem with revisions having time limit is that buyers profiles are not affected by timers and often they don’t care to hurry up with their part of collaboration. Normally not out of malice, they are just unaware how harmful late deliveries can be for sellers or have other things on their mind and schedule.
You would be surprised how common it is for buyers to request a revision/start an order without providing sufficient requirements or sometimes any requirements at all and then disappear for days/weeks/months.
And then the seller is left with timer ticking, stressing out about their whole fiverr career being damaged.
Orders are atleast somewhat protected from this by having mandatory requirements, but revisions not so much.
That being said, any decent seller should be able to provide you an ETA, if you ask, and stick to it. If they intentionally provide incomplete delivery to stop the timer, I wouldn’t bother with revisions as this is clearly not someone you would want to work with.
Cancel and report.
If it’s a complete delivery that requires some reworking, that’s a different story. But again, with a decent seller it shouldn’t take long to redeliver and they will be clear on when you can expect your order to be ready.