I've wondered if you cut the number of shows to a third of what it is now and gathered the vast majority of shows (maybe excluding the industry showcase stuff, circuses, and top bill comedians) under a kind of day pass at a flat rate if that might not resolve some of the chaos, confusion, and overcharging. It's a festival after all, so what if the city approached it like one?
Let's say somewhere in the wide space of £50 - £80 gives an all-access ticket for one or two days of shows and maybe a steeper but manageable £150 for a full week or maybe even the full slate of the Fringe. You could use it on anything first come first serve, but because people would want to get their value from it, they'd take more chances on actual fringe performances. Venues and performers could have a profit sharing minimum with incentives on number of seats filled. And performers could still gladhand tips at the end of their shows.
Get there early, show them a wristband, see the show. Maybe you even get a modest discount at participating pubs with it.
As it is, every show feels like an expensive risk where you have to decide if it's really worth £20 after fees to see a clown or an alt comic or a one-man play. I found myself even living here several years feeling less motivated than ever to take epdenwice chances and even more just paralyzed by the sheer scope of shows with very little information available on them.