it's just a game on a 8-Bit console from 1987, hence it can't be a that good game.
Castlevania sites Ive been to are some times the opposite, for example when comparing Rondo to the 16 bit cartridge castlevania games you will hear things like (you cant compare rondo to the snes and genesis games because the pc engine duo is a super powerfull cd based system)
it plays to clumsy.
People who are accustomed to the newer castlevania games will certainly make this point but if you want to play the fastest/agile castlevania character of the of the 16 bit era, you will have to play rondo( it will make the game easier)
the colors aren't that nice than on a SNES.
I have noticed it depends on how the person played each game, actual consoles or emulator, those who have played on a console tend to like the pc engine game more, with some of the stages in dracula xx(snes) having too many pastel colors or SCIV with its garish color usage, on an emulator the complaint Ive heard more than once is that rondo uses very bright or neon like colors, which isn't fitting for a castlevania game.
many people do claim that Akumajo Dracula X - chi no rondo is just an overhyped game. needless to say that those specific peeps are not an owner of the game or even owning the system it can be played on.
most of them also prefere a console called SNES/SFC or an other console which can't replay Akumajo Dracula X.
Polls will come up every so often asking what was your first castlevania game, the game that comes up most often in my experience is SCIV(It was my first as well) so theres allot of nostalgia around this game or for nintendo castlevania games in general.
About rondo being over hyped, the number one reason i hear people saying that the game is thought of the best old school castlevania game is because it was never released out side of japan, Bull...., lets take a game mag from recent discusions, GAME FAN, a magazine that will trash a pc engine game if it didn't have enough scrolls....here are some things they said about rondo.....(the perfect cd game, the reason we all got into gaming in the 1st place, the best konami game, better than any action game on the snes including SCIV), the quality of this game has been recognized from the beginning, of course the quality of any game is subjective and down to the individual.