Exactly. But now worse, because you don't get anything like that massive potential hit point pool to let you soak a ton of damage even if you didn't contribute much offence. Current moon druids are amazing at low levels, decline quickly through middle levels, become great when they are buoyed up by elemental shapes at level 9, and slowly lose potency until they get almost infinitely durable with unlimited wild shapes at 20. This is obviously not great design, but at least they are never terrible (the problem is that they are sometimes too good).
This version of druid solves the latter problem - they are not ever going to be too good. The problem is that they go from good at levels 2-4, to absolutely terrible by higher levels. It's just a long, slow decline as you level up. And keep in mind that over 60% of druids are moon druids. So this is going to affect a lot of players.
They are also significantly more MAD than other druids, because they are supposed to be tanky, but this revised version uses their regular AC and doesn't give them nearly as many hit points as the current iteration. So they are incentivize to get their AC as high as possible, which with medium armour means a dex of 14, and also to maximize their constitution, on top of their wisdom. Though I suppose one way around this would be to play as a tortle druid, so you could just focus on wis and con.
The fantasy of the Moon Druid is of transforming into a beast and tearing into your opponent (basically, the D&D movie, if owl bears were allowed), but this version is not that, beyond low levels. Instead, this version is transforming into a beast that is increasingly a mild annoyance, at best, to your opponent. And has moonbeam.
I think they should do the following:
1. Let moon druids round up for the CR rating of their beast, not down (this is a small buff but will let them scale a little better).
2. Pick six iconic beasts and have a CR 1-7 version of each at the back of the new PHB (this won't take that much space, just extra stat blocks on top of the base description. This will ensure that the moon druid will always have some interesting options, not just "mammoth."
3. Forget moonbeam. I mean, sure, put it on their spell list and let them use while wildshaped, but that's it. Instead, use the Level 6, 10, and 14 slots to buff wildshape further, so that it stays competitive as the moon druid levels up.
Example:
Level 6: Your attacks can deal radiant damage and as a bonus action you can gain resistance to slashing, piercing, and bludgeoning damage until the start of your next turn. You can use this ability as many times as your proficiency bonus, resetting on a long rest.
Level 10: While wildshaped, you can add your wisdom modifier to your melee attack damage rolls.
Level 14: While wildshaped, you can add half your proficiency modifier to your melee attack rolls to hit.
Those are just spitballing - I haven't worked out any math - but the idea is to let the wildshaped form stay viable in combat as the druid levels up. Because let's face it, a mammoth (one attack, +10 to hit, 4d8+7 damage) is not exactly striking fear into anyone's heart at level 18.
