[outsider]

This is actually impossible, as the very term RPI is opinion. Trying to measure the "intensity" of RP, which is by definition wide open to vast individual emotion and creativity, is impossible. There's no factual way to do it, it can only be done by opinion. At best you could say "95% of role players agree that feature xxx makes their roleplay more intensive". It would still be a value judgement, but at least it would be one backed up by the majority of roleplayers.

However, by your description of how the term came about, it is clear that did not happen. There was no massive, representative poll of RPers. Instead a group of RPers on a small selection of muds that shared similar characteristics decided for everybody what defines intense RP. The sample size was small, and inherently biased. The methods used to decide what makes intense RP were not sufficient to make RPI a factual label, and I'd go so far as to say that there is -no- method that could possibly make such a label factual, because it by nature is open to individual opinion.

If you want to stop having arguements about it, stop using a label that by it's very nature is a value judgement. If you don't like AFS, find another label that isn't a value judgement instead.