Moonbeam is broken. Moreover, Moonbeam getting a free 2d10 + 2d10 before the character(s) under the effect can react only further promotes non-Wild Shape combat.

Because:

You cannot cast Moonbeam while in Wild Shape (correctly implemented)
You cannot move Moonbeam in Wild Shape (missing implementation)
The damage output while in non-Wild Shape simply cannot compete with 2d10 + 2d10 burst with those puny animals Moon gets

So by adjusting Moonbeam, this also indirectly helps level out proper Moon Druid play. Hopefully, along with Wild Shape re-balancing as well.