Squirtle's fair nerf was warranted. Makes him not ********, which is a good thing. He can still kick arse, but it takes some more thinking to do so, instead of just walling fairs and bairs.
Regarding Dsmash on Charizard... you can buff Dsmash as you'd like; it still won't address Charizard's bigger issue, which I've addressed several times already. There's absolutely no reason to use such an unsafe move when Charizard has less risky and overall better options on the ground.
Dsmash hit on around frame 15 if I remember correctly, hibox is only on the ground (B+ is an aerial-centric game), and you're left open for a considerable amount afterward.
Opponent in front of you? Grab, grab, Fair, ftilt, jab, Boulder Smash (cuz that **** ain't no little rock).
Suspect a roll? Bust out that boulder again. If the initial hit doesn't land, one of the 9 rock shards will.
Case in point: Unless Dsmash is getting D3's ol' Fsmash "Earthquake" status, don't bother with it, because "fixing" that move won't fix his inherent problem at all.
Side note: I love Ivysaur more and more each time I use her. Olimars watch out: Ivy is gonna be the new definition of walling
.