I will admit I am usually likely to shoot the same score with a set of blades although I have not played any in a while but I am not sure about the blade having as good of a performance on off center hits.
If you can fit to a blade why can you not fit just as well to a cavity back or hollow iron? I can see the argument if a player is using a new iron that has too long and light of a shaft and too little loft, but that just means the player was not properly fit and not that they can't play a non-blade correctly fitted.
Many newer designs have quite a bit of tungsten out on the toe so there is plenty of mass there. If there was no mass there the MOI would be quite low. I don't think any newer hollow designs are putting nothing on the toe as if it were a driver.
Maybe I am wrong and I honestly prefer hitting a blade short iron for the most part but I want my longer irons non-blade please.