The me-cleaner is getting more and more bugfixes over time. For the average person simply sanitizing a firmware image to disable the ME will be enough. The question is more at what point are you confident you won't brick the system doing it.
I have not done any research recently in the success rate of ME cleaner, but it isn't that low, it usually works to the best of my knowledge, and once we have good documented statistics saying "this works most of the time" it becomes more feasible for those not directly involved in its development to start using it more proactively to get rid of this vulnerability.
The irony is that AFAIK the ME cleaner itself depends on exploiting some vulnerability in ME in order to disable it... so it may get more difficult in the long term.
The good news on that front is most board manufacturers abandon updates after a year or two. My ASUS mobo right now was released in 2013 and saw its last firmware update in late 2014. With the exception of the most modern boards, you can generally assume there will be no more updates for your hardware after a year or so.
I have not done any research recently in the success rate of ME cleaner, but it isn't that low, it usually works to the best of my knowledge, and once we have good documented statistics saying "this works most of the time" it becomes more feasible for those not directly involved in its development to start using it more proactively to get rid of this vulnerability.