It seems to me that there is no point to getting the IMC instructor restriction removed. Night a different story covers you butt if your a wee bit late coming home.
The chaps already who have a IMC can and do use you for safety pilot for the renewal (well i have logged 50hrs doing it) with a normal FI rating. And teaching IR after you hold one is just an extension of your FI course so the whole thing about restriction for IR qualified pilots is bollocks. In fact I have had renewals come to me for instruction not the a IMC qualified instructor because they are talking old pish. I just teach the method taught in my IR down to the IR mins and the students always sail through the exam (and enjoy it as well). And if i get 50hrs a year teaching IMC as a safety pilot what the hell. I reckon its more than some of the chaps who have the rating. Why the hell bother spending 1.8K on a dead rating.
There is nothing for a commercial student doing the rating so they don't do it. In fact it causes problems now because it affects your solo PIC time if you are hour building trying to hit 150hrs on the dot.
MJ