MW's appeal is pretty much the same as other Todd games, it's an open world with no real rules where you can (theoretically) go anywhere and do anything, and approach things in any way you want. Obviously the problems arise when you try to do basically anything other than hit shit with an axe/fry shit with a fireball and discover that the game either has no systems to accomodate you, has very shallow and broken systems (stealth, speechcraft, etc), or just outright refuses to acknowledge what you're trying to do. And add to that the fact that even the systems which the game does expect you to use (ie combat) are broken and shitty, and the fact that the open world turns out to be almost entirely static and unreactive and that almost nothing you do is ever actually going to matter or affect anything or even be acknowledged.
All the Todd games (MW/Oblivion/Skyrim) are frustrating as fuck because they're perpetually on the brink of being really good, but basically every single thing you do just ends up revealing that more and more of the game's promises are false. I think there's still not much else like them and that Bethesda deserve credit for trying things that nobody else was during a time when innovation and experimentation in games was on a massive downturn, even if they consistently went about it in the most lazy and low-ambition way possible, to the point where even a bunch of jokers like Obsidian could absolutely smoke them with NV.
That's where the lively modding scenes for those three latter TES games come in, I think - people are motivated to put a ton of effort into these games because you can kind of see the outline of something brilliant which is waiting to come to fruition, even though it never does. Over a decade later and I'm still hoping someone somehow hits on a Skyrim modlist which will turn it into the game it should have been but never will be.