I see no reason why an RNB Rotator would be worth more than a Rook. I would expect it to be worth significantly less than a Rook even in R mode. (The current mode would fine-tune the value just like current mobility would for normal pieces.) About half-way between a minor and a Rook. I am not even sure whether it is a major piece (i.e. can force checkmate on a bare King from almost any position).
I see no reason why an RNB Rotator would be worth more than a Rook. I would expect it to be worth significantly less than a Rook even in R mode. (The current mode would fine-tune the value just like current mobility would for normal pieces.) About half-way between a minor and a Rook. I am not even sure whether it is a major piece (i.e. can force checkmate on a bare King from almost any position).