Creating an original and completely unique character is more rewarding at the end than emulating a character from an established game. There are several reasons why:

First and foremost, if you use a character from an established game, you automatically know everything they do. As you may see from the rules, metagaming (aka, knowing about someone else's character and how exactly to stop him, instead of roleplaying the outcome) isn't something encouraged, but with a pre-established character, you may eventually give your opponent the gift of reputation. Your character may know even your own weaknesses by calling on the reputation of the character ("Hey, isn't that Cloud Strife? The one that wields the legendary Buster Sword, uses magic by means of magic spheres on his weapons and armor, and has a set of legendary sword techniques? Awesome, let me disarm him and shatter his weapons until he's weaponless!!!)

Second, making a pre-established character will shun people from playing against you. Believe me, most people (including myself) won't stand playing with a Cloud clone or worse, a Sephiroth clone. Making a character with a unique way of using magic, or an unusual form of combat is more rewarding at the end, since you know what to unleash your opponent, and your opponent will seek to find a way to respond to your attack.

Third, "stupid" attacks. There's one important thing to say: what's your definition of "stupid attacks"? If they're overpowered attacks that are unblockable and pretty much unavoidable, then it's god-modding no matter if it's the character's desperation move. That amounts to insta-win on the victim's part, as god-modding is severely frowned upon. If "stupid" is that an attack has to be called before being used, or that it has a different shape than the usual, or something similar: that's "quirks". Quirks make a character shine more than the usual. Flaws, quirks and virtues make a better fleshed character, since you have to play restricted by those flaws, and you get those quirks you enjoy used every time. Restricting a character with flaws isn't something easy, but it's something rewarding at the end.

Finally: it's alright you wish to play with the character concept you enjoy the most. I do, as well (I love to play with Paladins), but there's a greater reward in playing a character concept you aren't used to. It's much better at the very end, since playing with an unfamiliar concept may reinforce the abilities of your original character concept, refine them to cover possible flaws in execution, and refine your concept to show character development. While that last one isn't enforced in RPBing, refining your concept makes each battle with your character a new experience.

Hopefully clearing that (and not making it more muddled), I return to original poster's theme: variant rules.

I do believe that you and your opponent may agree to make the setting or the combat more exciting by adding variant rules, such as waiving basic RPB rules by notifying Cesar and by agreement within the parts. You can determine you're using rules outside of the normally established by clarifying in your first post. Some rules are better to be enforced (most specifically god-modding and writing parameters), but if you desire to waive some rulings, it could be worked with while at the same time becoming "legal" (of course, if the RPB area Mod, aka Cesar, approves of the idea). Placing traps or time limits per post or restricting some actions aren't limiting so as long as both parties agree, since you are effectively accepting the outcome for the sake of challenge.

One final thing: considering the RPB thread doesn't have a section for suggestions and the thread isn't an actual battle...could it be moved to a place where it may be considered? Or perhaps place as sticky, dunno. It's an intriguing concept, but this thread seems to break the dynamic of the forum section; I wouldn't want to see it closed, but I feel that it doesn't "belong" to this forum.