I, personally, really like the crowd pleaser idea. In one game I played in the past, Gladius, you control a school of gladiators and during the fight colored meters on the screen indicate the crowds current approval rating of your team and the opposing team(s). Depending on how much the crowd cheers you on, your team gets certain bonuses (increased Initiative, increased movement, increased critical hit damage, etc.). of course, you lose meter if your team is doing a poor job and you lose those bonuses.
Back to SSB, the crowd meter could be used to build up a FS and the more the crowd is behind your character, the faster it builds. This could, hopefully, encourage players to fight at their best.
Of course, if this is implemented, FSs would need to be tweaked since, as they are now, they range anywhere from borderline useless to so broken it's not even funny.