When possessing warden...

1. Player can do melee attack with no cooldown.
   2.Warden cannot fire sonic boom when possessed.
   3.Warden cannot burrow into the ground.
   4.Warden cannot roar.

Below are my ideas
1.The attack judgment takes effect only after the attack animation is completed. That's to say, after player clicked left mouse button, the attack animation begins, and after the animation ends, entity coincidents with the crosshair take damage.
2.The warden takes 1.7 seconds to charge up, then unleashes the sonic boom, which instantly hits the target as long as the target is within attack range. That's to say, all creatures that make noise in sonic boom range get glowing effect in warden's vision, and warden can select from them (left click) and fire sonic boom. However, if the target escaped from the sonic boom range in 1.7 seconds, the sonic boom will not hit it.
3.Warden can burrow into solid blocks. When player who possessed warden clicked left/right mouse button and hit nothing, warden will burrow into the ground, and player immediatly dissociate from warden, and then warden despawns.
4.Warden will roar after pressing shift. Like panda's standing animation.
I know warden isn't made to be possessable, but it may be better to complete warden possession as the wither did.

And here's my idea: make sure the warden cannot be possessed. Seriously, 500 HP and 30 damage (45 on hard)? No player should ever have this power. No bosses should be possessable, least of all the warden.

Wither is a boss too and cannot be possessed by default, but possessed wither can still do all the moves that vanilla wither has.

Well there must be some players want to have a warden hunt. One player play as warden and others try to kill it.

I mean I guess, but that sounds like something for a separate mod (sculkhunt once it updates maybe). In day to day Requiem gameplay the warden shouldn't be possessable.

Maybe. But as it's a option to enable warden possession by datapack, it shouldn't be left uncompleted. At least the no-cooldown melee attack should be considered as a bug.

There is technical support for other bosses in requiem already so there will probably be some for the warden. But as it is not intended to be possessed in the base mod, this kind of feature is not really going to be a focus of development.

Just to add to this, I also think it would be super cool if you were able to possess the warden. Ofc it's understandable why you can't, but maybe make it a gamerule since I don't believe pandemonium lets you possess the warden. Also to balance it more, you could add the debuffs that the warden has such as in being blind and only being able to sense vibrations. maybe that would look like the screen is completely black except for the particle effect vibrations make. But understandably this would be a lot of work but I do think it would be super cool.