I agree with @artportraits, and I also see your point @spackle.
The issue is that in some gigs, revisions may take way more than 10 minutes. If a revision will take more than 30-45 minutes, I think the buyer should be willing to order another gig. I am fairly new to fiverr, and I have come across AMAZING buyers. I give many buyers more than they pay for. However, I have also encountered a few buyers who I later realized were trying to take advantage of the system. One person once gave me instructions (which I clarified before starting) and after I spent hours working on the gig, changed his instructions, asking me for more.
Summary- While I believe in stellar customer service, I would not recommend that a seller gives unlimited revisions especially if they are very time-consuming, and if they go against previous instructions (or are related to new information that the buyer could have provided in the first place).