I will point out that being a remixer and remix critiquer are two different things. Proof - LIONTAMER. Emunator, who is a wip judge is another good example of a non posted remixer who gives out great critiques as well. That said, it might be harder for the newbs to be sure what critique to trust, as there are those that do know their shit, and those that, to put it simply - don't - or don't yet.
I think that being a posted remixer will get you alot more respect from a musical standpoint on ocr because it basically proves that you are above a certain standard, but that doesn't always mean that those that aren't are completely hopeless. However, if you want to be taken more seriously from crits, then getting a posted remix is pretty much key because it gives you that status that you aren't a newb who doesn't really have a clue, at least to those that won't be able to tell the great crits from not so great crits.