WOW! 14 pages on this. Get ready for more. I started racing 15yrs ago and how things have changed, for the better I think. I have seen classes come and go and then the Numbers started dropping, not sure why, but the racing survived thanks to the die hards. In the R.S.A we followed the trend and introduced a 21.5 class 3yrs ago, and on National level we had more than 30 entries per event. Rules were quite basic: pro chassis,fixed timing motor, blinky esc,FDR limit etc. This was considered an entry level class meaning if you run any other class you coud not compete in 21.5. And after two years that`s it, up you go to a faster class. As a relatively small RC community (max 200) racers and no REAL funds , scruiteneering was always going to be a challenge and cheating started to creep in. This killed the class. And as the worldwide economic crunch was hitting us as well, The controlling body had to downsize and the class was dropped a year ago. One year later and the interest is growing again so in hindsight there is space for 21.5 as an entry level class, but Nationally .... I don`t think so, unless the numbers are rising at club level,with stricter rules, which I will enforce at my club. To be successful an ETS format should be employed, Handout motors or in F1 terms, Parc Ferme, rule to be applied where the club or controlling body need to take possesion of the motors/electronics until race/practice day..... Difficult to enforce but excecuteable. And like in all the threads I have read if you want to go faster move on.
So in closing, there is place for 21.5 as stock and I like to qoute the famous line from Field of Dreams movie "I you build/host it, they will come"