Only because the DM allows something that should be impossible.
Bad DM is bad.
This is a bit off, Paul. There's nothing bad about that DMing given it's a Find Steed spirit-horse (which is magically intelligent and all sorts). If it was a real horse, well, then it's more about the realism/heroism level of the campaign (including on how well-built those roofs are!).
Agree re: squeezing in most dungeons though.
It's almost like monks get compared to the damage of a GWF, the AC of a plate and shield fighter, the hp of a Barbarain, the mobility of a rogue (or is it a horse), the saves of a paladin and somehow not being able to do better than all that combined at once makes a monk suck?
That's not a fair assessment of this thread, though. Even if you compare to just one of the given classes, they don't look great. As with all 5E classes, they're basically playable and not grotesquely out of whack (which remains an achievement that only 5E and 4E have managed), but they're a class in search of a role, and the only role they seem to be able to find that is clearly theirs is "Spam Stunning Strike". The Ki limitations are also a major problem until they're not.
I mean, I think one thing that would help slightly would be to get rid of the stupid linear Ki gain. It just doesn't fit with 5E's design. More Ki gained at lower levels, and less at higher would be a good start.
Beyond that, finding ways for them to work beyond spamming Stunning Strike is going to require some sort of redesign outside the scope of 5E. For me, I think what is particularly sad is that the ability they are likely to get most mileage out of (arguably FoB is equal, but going to be less noticed) is a pretty dull-but-solid one that mostly benefits everyone but them, and keeps having to be used repeatedly, rather than the subclasses having equally cool uses for Ki. I mean, honestly I'd consider removing or limiting Stunning Strike to open up that design space.
The versatility is great in theory, and it can work in practice, but you run out of juice terrifyingly fast at lower levels, which is where people play most campaigns.
For me it feels like the Monk suffers in three ways - firstly, because 5E's designers inexplicably (and still, to judge from Theros), wildly overvalue unarmoured AC, unarmed attacks, and to a lesser extent, mobility. Unarmoured AC is very rarely more than an aesthetic choice, and both it and unarmed attacks are often objectively worse than the alternatives (esp. as magic items get involved). Mobility is likewise, in my experience anyway, rarely an issue (and even less of one in TtoM). Secondly, because it leans hard into nostalgia, in terms of what abilities it has, rather than really being considered in a modern way. Thirdly, because it's a half-arsed design, which leans hard on an ability that is inherently a bit boring and mostly benefits others, and you have to keep using.