Alright, let me start off saying I'm not opposed to rule changing, especially if it makes Brawl more enjoyable without TAKING anything from it (banning, to be specific). What I want to emphasize is that 1 stock Bo3/Bo5 will ruin our current ruleset, counterpicking, and overall character MUs/metagame. My honest suggestion is: if we want to try something new, using a 2 stock Bo3 unity ruleset would be ideal.
This is worth trying too.
Obviously Brawl isn't a traditional fighter, nor have we ever tried to revolve our ruleset around anything we, the community, haven't made ourselves. That being said, this new idea of making Brawl "faster" and more efficient in playing out tournaments has its pros, and its cons. For one, Brawl won't become faster, but rather the entire set will be. Characters will camp harder, and NOBODY will want to approach anymore. I can guarantee you people will try to run the clock, and MUs like Marth vs. Falco, Snake vs. D3, Ganon vs. ICs (lol), etc will become longer and less entertaining. In regards of efficiency... yes, I will agree that tournaments will be run quicker. However, this is BRAWL guys, this game is ALL about patience and utilizing your spacing like you're making a move in chess. One can only strip so much from a game that absolutely requires you to not approach (at times) before it becomes something completely different.
Just because you will choose to camp, doesn't mean everyone will, just sayin.
Counterpicking will also become hectic, and the adaption of player vs. player will also become less utilized. An example of this would be Street Fighter. You have 2 "lives" per match, and in most cases, you use your first one to feel your opponent out. When you lose your first match, you lock your opponent into their character, and therefore you can take all that you learned from the previous match, and counterpick. In Brawl... that won't be the case. If you lose the first match, not only do you have to choose between re-adapting to a different stage (your choice to CP a new stage, obv), but you may have to re-adapt to your opponent's NEW character. Honestly, how s that fair to anyone? And before you mention, "we can just lock the winner with their character," how is that fair to them when you can hard CP them to a stage AND character? Should Arty be punished for winning game 1, and then CP'd to lylat against a IC? Anyways, that's sort of a tangent, but I hope you get what I mean.
Imo counterpicking would be stupid with this ruleset, and it should just be random neutrals for the whole set instead of counterpicking. Keep the character counterpicking the way it is already.
Finally, even though I slightly covered this in my last point, character MUs will change way drastically. Characters like Falco, ICs, Lucario, D3, and Snake all hold HUGE advantages over respective MUs. Get grabbed by ICs once, and you're dead. Cool, did you learn what you did wrong? Maybe, or maybe you made an input error and died. D3 CGs you once, and you're half-way dead, awesome. Lucario gets to 100% and proceeds to fsmash you with his almighty aura and you died @ 80%... sweet. Even characters like Wario can air-camp and go for early wafts, and there's nothing most characters can do. Having 2 stocks will at least eliminate these mechanics, and give you a comeback tool.
To that same effect, you only have to gimp Falco once, kill Nana once, gimp Snake once, etc.
Pretty sure Lucario isn't stronger when both characters start at once stock, since he has no stock disadvantage to begin with, if anything, he'd be weaker.
Who's to say Wario won't just air camp for two stocks and waft both times? Hell, some do it right now with 3 stocks...
If I had to summarize all of this, I feel like 1stock takes away more than it gives. It takes away depth, adaptation, our metagame, MU tools, and enjoyment (last thing is subjective lol). 2 stocks seems like it could be legit, and I feel like it's the best first stepping stone we can make.
It also makes other characters possibly viable... Pokemon Trainer for instance. Adaptation can still exist in a one stock match, and if it's Bo5, there's still plenty of time to learn.
edit: my copy/pasta from notepad made everything messed up <.<