I will say, the biggest problem that faces Numenera, and the Cypher system as a whole I guess, is the "Spend pool to protect pool" issue.
Each character has 3 pools (Might, Speed, Intellect), which also constitute your Stamina. When a pool hits 0, you go down the Damage Track one step, which is the Actual Damage of the system. There's a lot of worry that like "Why would I spend 3 points of Speed to make this defense test easier, when I'd be taking 4 Might points instead?"
And this is a problem! You're spending resources either way, and spending pool for a defensive roll doesn't even guarantee you'll be successful.
The most obvious note is that this constantly puts you doing cost-benefit analysis with those two tracks in particular. Might is the primary pool affected by attacks, and Speed is your most common defense roll (dodging the blow, or positioning, blocking with quickness, etc). So if you're a Glaive with 20 Might and 10 Speed, you'll probably opt to take the Might Damage for awhile, before spending Speed to keep some of your Might available for other hits, or tasks, or hell, to activate some abilities.
Edge helps mitigate this some, since you can use Edge to reduce the cost of the associated Pool by that amount. For example, normally to apply Effort on the attack dodge, the thing that makes things easier for you, you'd have to spend 3 Speed pool to apply effort, then you subtract your Speed Edge from that cost.
This helps but doesn't completely address the issue for some people. Everything essentially is Cast from HP. For some tables, that's great! The ebb and flow is what you want! You're adventurers doing stuff. But for cautious players, they won't have enough Edge to mitigate enough costs, which makes the game less interesting or fun for them. So instead of doing things to make a roll a 9+ to succeed, they take the 12+ because it's better than spending points.
And honestly, I don't know how to address it. I saw some people made "Health" pools out of Speed+Might and a Mental pool out of Intellect to take damage for you, and kept the 3 pools for abilities and pushing yourself, but I don't know if I like that. Planescape: Tides of Numenera had a health system giving you a 4th pool that was just your Health, but I don't know how to properly derive that in a way that feels satisfying. The book for working stuff from the video game into the tabletop doesn't have that (but I ABSOLUTELY want to use the Tides system, it feels like a neat way to tackle reputation and like... Descriptive? alignment, since it's always changing).
I think this is absolutely a great game, but I can see a very obvious shortfall that will put people off of it. While implementing a workaround, like the Health Pool idea, can mitigate the problem, it might also hinder the system as a whole. I haven't run or played the game enough to know though.