can I ask why you're designing a game to put in a game when there's mechanics readily available for everyone to use?
If you try to see the problems faced by role players from our perspective, then this solution might make more sense.
Problem #1 - Not everyone who plays wishes to level. Leveling takes a very long time, and for some, it is seen as a very boring chore. Some of us find it far more enjoyable to focus on the role playing side of things and so we do not level that much, or do not level at all. Because of this, there is sometimes a huge difference in skill level. The difference is so large that an untrained character cannot be matched against a fully trained character. This means that if you use stats to resolve fights and you wish to role play a strong character, you have to spend a ridiculous amount of time leveling.
Should only maxed characters be able to play very strong characters?
The majority of players who I have come across who have maxed characters don't RP, they just train and train and train... and train. They don't have interest in RP or don't have the time because they need to train some more.
Typically, you want strong characters to be good, solid players and not people who are going to screw up a role play by saying stupid occ things that don't make sense, derailing it because they can, or just pushing their weight around with their maxed skills and not providing any entertainment in return. As it is now, role-played characters are as powerful as other players allow them to be. There's a sort of balance here as a result.
Problem #2 - The thrill of roleplaying vs thrill of mechanics fightsFor many of us who role play, we find it far more immersive and enjoyable to role play our fights. While a fast paced mechanics duel can last for seconds or minutes without the hassle of reading and calculating stuff, they lack depth, description, and detail. I suppose its just a different type of thrill.
Problem #3 - difference of opinion and the need for conflict resolutionAs you would imagine, there are sometimes disagreements about the outcomes of rp fights - ones that the mechanics system would automatically resolve. For many of us, we can make mutual judgment calls about success, failure and damage without a problem. The problem is when you try to have a cooperative rp conflict with someone who has very different ideas of what is fair and plausible , it can take the fun out of the game. A set of rules and conventions for resolving this with /roll is what we are after.
Problem #4 - handicap and difference in statsThere are times when you want to overlook large differences in stats and skill so that you can play with a newer player as if they were much closer to you in stats. To date, there is no way to give a weaker player a "handicap" so that they can participate as if they were close to equal. Roleplayers will sometimes overlook shortcomings in stats and just treat the character as being as strong as they are intended to be. This works well with players who can see eye to eye, but again, tends to not work when players have very different ideas about what is fair and believable.
Lastly, I was thinking that such a system could open up more possibilities for leading events. I recently lead a small event with a few players where we discovered fissure in the death realm and ventured into it. We encountered a seemingly desolate and threatening underworld city and began to explore it. Upon entering a strange building one by one, the door through which we entered was slammed behind us, and in the complete absence of light, we were attacked by something gigantic, and vile....
During this small event, it occurred to me that if I had planned out an entire campaign complete with traps, challenges, obstacles, and rewards, it could have been epic. It was at this point that I saw how an enhancement like a dicing system plus a formal method for calling success and failure on various feats could enhance the game.
I hope this helps.