I also think the old villains aren't that great. Yeah, they're evil, and that defines them, with entirely 2D motivations. Gaston's a philanderer who wants to bang Belle, Scar wants to be King despite his brother doing nothing wrong (ie it's not that he thought he'd do it better, it's that he wanted to be King full stop). Jafar's just evil. Yeah, they have great animation and great songs, but they aren't great characters.
Dr. Facilier is great because he has the songs and the animation and a more interesting motivation (beyond his initial one of simply wanting money) - that he's basically in debt and is desperate to get in his debtors good books. The "bad guy" in Bolt is a clever one, because for the first half of the film the bag guy is basically in Bolt's imagination and in the second half it's trying to fix the fallout from this mistake. Tangled's one is a mother who has genuinely come to love her "daughter" even though she needs to imprison her in order to keep herself alive. Frozen has a villain who is bullied by his brothers (which Mufasa didn't ever do to Scar) who then has a chip on his shoulder and, being so far down the line of succession, has no recourse but to find another kingdom etc. I'm not saying these are all high art or anything, but the reason you don't have "strong" villains any more is that they don't all pop up in the first act with a song, some nazi dancing and what ammounts to an "I'm really evil" monologue. It's a bit more nuanced than that now and what you lose in merchandisable villains you gain in interesting character.