I can't really say whether the range is better in Smash or PSASBR. I only played the in store demos and betas of PSASBR and I was admittedly very impressed by the variety of the characters. The "range" may very well be more pronounced than it is in Smash.
Of course, keep in mind that more differences in characters isn't always a good things. Smash characters are WAY more varied than the characters in typical fghting games. This is part of what makes Brawl special, but it's also what makes it have some major balancing issues. When one character has access to a mechanic that other characters do not, this can mean major problems in balancing. In Super Street Fighter 2 Turbo, Akuma had access to an air fireball. This one feature made him practically unbeatable in tournament play and necessitated a ban. Similarly, Magneto, Storm, and Sentinel had unique movement options that helped make them broken in MvC3. In Brawl, MK's multiple jumps along with access to a sword make him overpowered. You'll notice the top characters in the game are those that have access to some unique mechanic, whether that's Diddy's Bananas, Olimar's Pikmin, Snake's grenades, or Ice Climber's chaingrabs. I'm certainly not saying that variety is a bad thing, it's what makes me love Smash, but it also can be a double edged sword.
Out of the characters in Smash it's hard to say which two are most unique. Ice Climbers and Wario are entirely different characters. The Ice Climbers rely almost entirely on their grab game at high level play, by punishing any slightly misplaced attack. Meanwhile Wario relies on his bizarre aerial mobility to apply constant pressure. Diddy is a character who focuses on using bananas to keep opponents off balance, and Pokemon Trainer is a character that completely changes with each life. Sonic spends most of a match travelling with his side and Down B attacks and using hit and run tactics while Ike is a straightforward brawler.
In other words, their are lots of unique characters, and it's hard to say which two characters are most different. I will say that Smash has pretty much the best amount of variation among any fighter I've ever played. If PSASBR is better in that regard, then that'd be impressive, but criticizing Smash for having characters that are too similar is ridiculous.