Dominate Felines and Panther Trance kind of overlap.
as would the dominate part of Command Thrall. I think I'd just keep the charm monster part of Command Thrall.
Curse of the Panther Lord looks good, though I don't think I'd include giants.
That, and the Trance's ability to send simple commands to the thralls, much like dominate. So I'm not opposed to allowing the panther lord to command/control the thralls, but I'd prefer to reduce redundancy in the mechanics.
As for the curse DC, what about 20? It shouldn't be too easy for low-level types to avoid.
I can go for all that. Care to write it up?
Yes, all that is good.
Oh, let's go with Cha-based on the curse.
Right now, it's got AC 22 with the chain shirt and the +4 natural. That's about right for CR 8, at least compared to something like an erinyes. So I'd go with that.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.