I don't remember Nimoy saying anything about Tuvok/Russ either and he was leaps and bounds better than Blalock/T'pol. In fact I would bet he didn't see one single second of their performances, he was occupied photographing naked PLUS++ sized women.
I think the only reason he did interviews about Quinto was because he was in that movie and Quinto was actually playing his
character and they worked
If you asked him about Blalock and Russ he would probably say, "Who now?"