Naga: cannot copy legendary creatures (copy is legendary) so cannot be a mutation target for Otrimi and Brokkos. That might render it not worth inclusion. On the other hand we have plenty of other mutate creatures and copying those might be very fun.

I should add Return of the wildspeaker from the another precon deck.
Primal empathy might be also interesting here.

Lazotep plating might be good protection.