It's just because the games are older and they have already played them that is all. Sonic Adventure DC was released what 3 years after the DC version? It's still a better game just no longer cut it in their opinion.
Yep, just look at these IGN scores:
Super Mario Advance: 8
Super Mario Advance 2: 9.3
Super Mario Advance 3: 9.4
Super Mario Advance 4: 9.5
Yep, they really tore into those remakes/ports.
Oh and look at this:
GTA: SA PS2: 9.3
GTA: SA Xbox: 9.5
Let's not forget how no critics were at all nice to Super Mario All Stars.
And what about this:
RE4 released on the Gamecube and got a 9.6 on the GC. 9 Months later it releases on PS2 (older hardware) and gets a 9.3 (not too shabby).
There's nothing about games being old that totally explains this (I mean the whole industry wet itself when Mario 1 hit the GBC and a colour update of the original GB Zelda did very well critically). Sure, the game reviewers are genrally biased against "old school" games, but that doesn't explain why they'd complain about a well done port of a game from this generation. GTA and RE4 don't seem to have suffered that fate. The fact is that these games just really don't do it enough to impress. Whenever I play one of the ported versions I get the feeling that when Sonic Adventure was originally being made Sonic team was saying "not enough, we need to give these gamers more if we're going to wow them with our new product". Then I see them years later making the Gamecube port and saying, "okay that should be enough to keep the little [expletives] happy".
In a market that's already flooded with sequels, the port of an old game could not be more in line with what I think is wrong with the industry. Think about it, it's like a sequel- but without even a new story. Yah! Soon all systems could produce the exact same product and the system with the most slightly tweaked graphics can win. It's stuff like this that kept me from buying Mario 64 DS and from buying an N-Gage anywhere in the first year of it's life.
Maybe I'm a purist. I mean, if they took Moby Dick and added 5 new chapters, would you think it was a better book? If they gave the Mona Lisa a 3D hlogram where her smile turned into a frown if you looked at it a certain way would you all be extolling its virtues? The game was fine the way it was on the system it was intended for, not as the game equivalent of a DVD with *gasp* multiple endings that are less good than the original ending. Now if you'll excuse me, I'm visiting my parents and my father just gave me a record player he was going to throw out and I have to listen to some records in their original needle read glory.
(Seriously, I just got a turntable, how cool is that )