I would love to get feedback on a proposed set of rules I call Ultimate Go, which is extremely simple, yet solves the issue of free teire.
The rules are actually (as I found out at some point) based on "no pass Go with prisoner return", but with a slight complication via the device of an "ultimate prisoner", designed to solve the issue of free teire. Briefly, the aim is to make ever teire move cost something, regardless of dame parity (in the sense that if you don't know the Komi you risk something when playing a probably-unnecessary teire move).
See
https://senseis.xmp.net/?UltimateGo (there's also a detailed analysis there, of an earlier, equivalent formulation of the ruleset).
Thanks lots in advance!