I think RP samples are perfectly fine to ask for, without being guilt-tripped or heckled for thinking someone's better than everyone else. The simple fact is that if you RP like:
*looks around*
then maybe you aren't cut out for those more put together RPs. Roleplaying is a skill, since it's just a form of good storytelling. It's writing. Younger people may have a tough time will spelling, or large vocabulary, and that's okay. They will learn.
There is definitely a sense of maturity with the way you RP. Is that wrong? No.
The way you structure a sentence / tell a story changes as you age. The above example lacked any meaning, purpose, impact, and detail. It could have just as easily been omitted and nothing would change.
As long as users remember to not powerplay, and keep their posts meaningful I don't think length really matters as much, since some people like to put requirements on that. You can't really force a story to be told better than it's going to be.
The whole using *s or -s or some type of indicator to express action is so widespread, it's pretty much the first form of RP anyone learns on the internet.
If you decide to aspire to become a "good" RPer, then it should become your goal to improve from there.
While those indicators work for a vast majority, their purpose is convey short, concise action quickly. Which they do. I use it mostly for speaking OOC, since I don't find it appropriate for storytelling.
What most people call "forum-style" RP is much easier to read and comprehend, not to mention it gives more opportunity to fill with detail, especially when telling from a third person view.
Ex:
*bites, hard*
vs
Rayne suddenly lunged forward, jaws open, ready to catch her victim by the throat.
Even keeping it very simple, as I did, still plenty more detail packed into that one statement.
So I guess it just comes down to whether or not your RP is just for the sake of RPing, or something more. A story to be told. Most often those "mature" RPs are just trying to tell a story, based on some sort of vision the creator had.