I think that as Brawl ages, people will see the importance of "safety" in a character. Having only a few small disadvantages and only a few advantages is usually better than having a lot of greatly advantaged matchups and having a lot of greatly disadvantaged matchups.
If your character's worst matchup/few worst matchups are 6/4, that's viewed by the community as "winnable". If your character has even 1 or 2 65:35 or harder matchups, it becomes less likely you will win that.
Take a double Blind pick for example. First match, you have no idea what he will pick, he has no idea what you will pick.
For the sake of argument, the stage is FD.
Take Marth. AT WORST, he might have it 6/4 or 65:35 against, say MK, there. He also might have 55:45 or 6/4 against Snake, and 55:45 against Dedede himself while going relatively even with the rest of the cast or having a slight plus on them.
Now take Dedede. AT WORST, something like IC's/Diddy/Falco will happen, likely being 65:35 or even a possible 7:3. He also will have to deal with MK, Olimar, and maybe 1-2 more bad matchups. Now, he will have a lot of 7/3 or 65:35 in his favor, and a few even matchups too.
Marth is the "safer" pick in that instance. He might not beat a lot of people 65:35 or 7/3 like Dedede, but he doesn't lose/have as many bad matchups as Dedede. Pure odds wise, assuming the other guy picks a random character, Marth is more likely to get an even or better matchup, while Dedede is favored to get not only a bad matchup, but one of the more severe ones compared to Marth. Even if Marth is matched up with his worst matchup, it's generally seen as "winnable". If Dedede is matched up with his worst matchup, it's seen as "extremely hard to win" or "very very hard to win".