I’m disinclined to run pretty much any tabletop game that outright uses character levels as a form of progress, and fortunately for me I live in a time when most such systems have been banished to the land of wind and ghosts. But I don’t resent level systems in MMOs – most of the games that try to do away with them wind up with their own problems in implementing a realistic gauge of strength (The Secret World) or have them by a slightly different name (Skyforge). I don’t think that this is the only way to do things, but I accept that levels are usually a necessary evil based upon the ways that video games work compared to tabletop.
Then again, I think we all have systems that we don’t necessarily like but we can recognize as necessary evils. Weak combat in sandbox games in exchange for more non-combat options. Cumbersome crafting mechanics in exchange for more player agency in crafting. Some systems are just plain necessary evils. So what systems can you think of that you don’t necessarily like but recognize as the best functional compromise?