The problem with the One is that the disassembly is difficult.
It was a lot easier to take a Rezound or One S/X apart to do a JTAG or glitch by loading the clock or data bus.
If you look at the teardowns of the One you can see that virtually all the chips are BGAs and the only accessible components are passives.
There is a very good chance that one of the passives is connected to a pin that you want to get at on the processor or flash - the problem is finding it.
I would think that the potential hardware damage possible by glitching the bus is too great to even bother trying to find a glitch point.
Hardware damage is not reversible... software damage is so IMHO JTAG is really the best option for the average joe, or the guy that has tons of cash to throw at phones to try glitches.
I have not needed S-OFF myself... the HTCDev unlock suffices for my needs and I am not stupid enough to tinker with the radio on a cellphone.