Not really.  I mean I've seen those arguments and simply refused to entertain them.  Both you and KaVir are more perceptive than that.  Well I have some faith in that anyway.  You may have noticed that Aristotle responded angrily when KaVir suggested RPI either meant anything (or nothing) or met a partial list of criteria he listed.  What prompted my little humorous tirade was also the hint or suggestion of a literalist position or anything or nothing at all position.  i.e. PK just might mean killing off your users then.  heh.    

It's how the argument is framed.  If Aristotle and myself don't agree with the list of criteria posted (as I think was outlined in the first 6 or so posts), then RPI just might as well mean nothing or anything.  A serious argument?  I don't think so.

I believe, and presume Aristotle does as well, like many mud acronyms the definition of RPI is a term describing an analog state.  There are mud games which are clearly in the RPI spectrum, mud games which are mostly in that spectrum, some on the edge of that spectrum, and games which are clearly outside of that spectrum.

Interestingly the same is true of MUD itself.
Is chess a MUD? Is IRC a MUD? Is Doom a MUD? Is Ultima Online a MUD? Is Mush a MUD?  Are the TMS forums a MUD? Is Armeggedon a MUD?  Is Baseball a MUD?  Is Diablo a MUD?  Are games with graphics MUDS?  Does a MUD have to have combat?  Are games without elves MUDs?

Quite likely you'll get some resounding no's, yes's, some maybe's, some WTH?!s, on answers to those questions.  Same is true of this RPI or roleplay intensive/immersive term.

It seems clear enough to me anyways that it's indeed a subset of RP or role-playing muds.
Knowing a mud is deep into that RPI spectrum is somewhat useful to me too.  I can then avoid it when I want to role-play.