I'm going to be honest, I suspect players that have trouble playing monks are because they just don't know how to use them to their fullest potential. It's true for all "problematic" classes since people almost always compare their playstyle to a playstyle completely different than the relevant style.
I've generally seen that's it's rarely the player's fault.
The monk will have trouble when :
1. Short rests are in short supply. The DM is, more often then not, in control of pacing. The players can have input, but often don't.
2. Mobility is not an issue. In many campaigns (often theater of the mind, but sometimes map /grid based as well) positioning, movement, obstacles, etc. are not much of a thing. The charscters mostly stand and fight or move, but without much relevance. The monk will suffer here, as much or more than even the rogue.
3. They take in a role they just don't fit. Monks make terrible tanks, for example, yet if there are 3 characters and the other 2 are squishy - the monk's player may try to tank. This will almost certainly have unsatisfying results. This is closest to your point, but the DM here, should really compensate a bit for lack of roles. At the very least, point out to the players.
I'm sure I'm missing some, but the point is - those are on the DM, not the player.