I don't like to nitpick, but Phanpy actually had a battle lasting about five seconds against a Machoke that is just about good as forgotten, and it did beat Macey's Slugma after it took a Water Gun from Totodile... and for the record, Phanpy did retain it's playful personality, according to the character bio's on the mainsite, and the picture proves that, Phanpy not evolving in Johto is due to the same reasons why we never saw jack of Heracross and why Cyndaquil didn't evolve in the first place, those were the writers noob decisions...
I wouldn't like it if Cyndaquil's and Totodile's personalities, or quirks were entirely thrown away. That would just negate their personalities or whatever they had left at the end of Johto, which would mean there will not be any development characterwise but reinvention or modelation, and quite frankly that is even worse. There are ways to work around those character quirks to give the freshness...
Cyndaquil: It's backing up scared into that rock. Seeing that makes me think that it still is a bit timid. Then it evolves ala same ol' same ol' rocket scenario, and gains more selfesteem and the edgy look that comes along with Quilava. In this case you are right that an evolution is the quickest way to change a pokemon's character, but outright throwing away is different, I mean look at Ash's Charmeleon for those three episodes it existed, there's nobody besides me who actually likes it... For Quilava it will probably mean more edge and selfesteem, but after it blasts TR away, I'm 100% sure that it will give Ash a smile in acknowledgement...
Totodile: It could still have the jolly personality, and dance a bit. If it doesn't evolve then it's still fine. If it evolves, I can see it dancing less flamboyant and childlike, and adopting more cool moves that are less flashy. Just a little headbobbing on an imaginary beat with it's arms crossed is still a form of rhythmic movement as it comes out of the pokeball. Thereby it would look less childlike without the jumping and arms and feet going everywhere and instead would look cool, which would fit a Croconaw.
It would still keep that 'dancing'-idea, but toned down, to a more mature idea, which is what I call development and a better idea then just outright removing it.
Think of it as Totodile being a child, which dance with all their energy and arms waving about, while adolescents try to come off cool and try to restrict their movements as much as possible. (This is excluding break dancers of course)(Which is what I want to see Feraligatr do).