if it just came out? do you think the reviewers would've rated it the same now? right now it has more things to compare against such as red dead redemption, gears of war 2, uncharted 2 etc...

Well, you wouldn't have a title like RDR if GTAIV wasn't succesfull. Despite what people may say, GTAIV is worthy of the AAA

I don't think so, there is something rotten in the review system, no one wants to be the one who is different from the mass, at least in big budget, big marketing campaigns games. GTA is one of the biggest franchises, it's the same than MW2. Did MW2 deserve the grades? I don't think so, but the hype tsunami was too much for the reviewers.

A lot of games from 2008 would be rated different, like Gears 2 and GTA IV.

Child please.

Besides RDR no other openworld game has rivalled GTA4. With the exception of a graphic comparison there is no way you can compair the likes of GeOW2 and Uncharted 2 with GTA4. Besides GAT4 would have looked better if released today (maybe even played better).

Just Cause 2 is fun and all but in no way does it have the quality of GTA4 and RDR. These games offer so much more depth and detail and that is what most reviewers look at. Doesn't mean that some reviewers and many gamers have a different perfective. Just look at Yahtzee, he found GTA4 boring and loved Saint's Row 2.

But most reviewers would appreciate that what GTA4 does and rate it AAA for it, even today.

The only reason GTA IV is so polemic is because it was rated as the top gaming experience of this generation and for many people, including myself, it was quite boring.
Nevertheless, I can still recognise why so many people like it so much.

No.

Hype swould still reign supreme. Point in case - Modern Warfare 2

It would still be one of the highest rated games of all time.

Maybe a bit, but it still deserves AAA status.