Harmony of Despair looks great and the characters are displayed in far better quality than those GBA and DS screens. 2-D Castlevania is an art, and long time fans don't have a problem with those graphics.
Don't speak for everybody, please. Asset wise, the game looks like an amateurish PC hack done by one guy, as the levels in terms of background work are hit and miss when it comes to a lot of elements. I can get the same type of visual fidelity out of the GBA and DS games by playing them on an emulator on a full screen viewing setting, with the extra facet of the stage design actually being coherent and making sense.
The only things Konami put an effort into were the new artwork renders for the characters and the music. Everything else screams this strange, uncanny design behind it. I'm willing to bet Westgate (A contracted developer for the game) was more involved with the development of the game than IGA's team, because despite his games having some shortcomings, they usually have meat to their bones. I keep trying to play this, hoping to like it, and the games almost pervasive weirdness makes me want to turn it off only a few minutes later. Nobody is really around to play the game anymore, making the purpose of getting characters absolutely useless (there's usually nobody around online to grind them up). I mean, I keep having this inner battle with myself. I end up thinking to myself "why do I keep playing this? There's no story, rhyme, or reason behind the games purpose, and nearly every other game in the franchise has more reasons to play those than this."
Maybe I'm waiting for the Lords DLC and use HD as filler, but as far as I'm concerned this is far and away from the traditional, real Castlevania games. Similar to Mario Kart when compared to the Mario platforming games. Even Judgment has more of a connection with the regular games than HD does. They put more of an effort in making new materials for that than with HD, and that should say a lot.