Should they nerf or delete Mosaic?

Personally I thing they should bring it back and leave it as is with the exception of changing that

Gul rune into a

Sur or

Cham rune (give those runes value).
Instead they should slightly change the Martial arts. Different

Charge types should not be stackable. If you have 3 charges on

Phoenix Strike then the moment you get one

Charge of

Claws of Thunder all non

Claws of Thunder charges should be deleted. Nobody ever charged up multiple skills before so there shouldn't be too much complaint about not being able to do it now.
I don't think the only viable martial arts build ever should be deleted though. Without Mosaic martial art build are not viable in Nightmare and Hell difficulties and they haven't been since the assassins introduction in 2000. I have failed many MA build attempts since my teen years.

blizzard current doing is very correct. Ladder is clean place for people want to try new things.

Let Mosaic available only for people like old stuff...

And you can see, since warlock come in play, Mosaic no longer important. not much people talk about it or buying it.

it is almost frozen for most player. You have warlock, why you care Mosaic that is less fun and not even strong?