I feel like it would be difficult (hopefully!) for them to remove the ability to transfer to hotel programs from the Cobalt as every tier of Membership Rewards points can be used to do this. They'd have to make a whole new category of Membership Rewards points to facilitate that.
I can't see them making any changes (hopefully!) to the Cobalt based on this feedback, it's not like they weren't already aware of this.
And if someone has both the Marriott Bonvoy card and the Cobalt card, isn't that better for Amex anyways?