Alrighty than i guess if someone wants an advanced one they can advance it
I think the extra skills and feats would make this a bigger challenge maybe one more cr.
i think Its safe to remove the red parts too
Not sure the difference is enough to warrant a higher CR. I'd rather give it something extra so there's little question of it being nastier.
The simplest solution would be to allow it to have 2 slams as a full attack. That'd be worth a +1 CR.
I like 2 slams on the smart version, and the single actions for the mindless version works, though then we might want to reduce that one's CR by one also.