I also been a GTA Fanboy since '97 myself. But the character system in 5 and 1 are nothing alike. at all. Not even close. The characters in 1 didnt even have a purpose, because essentially it was the same no matter who you chose. It was choose to give the user a choice.
That wasn't my intention. I just wanted to point out that they now reconstruct ideas that they had already in the old titles. Their last attempt to bring in multiple protagonists was in San Andreas by all accounts. It was skipped eventually. In a lot of magazines they say "it's going to be the first title where the player can choose from different characters". It's because they have never played the first title!
I can predict if a new Grand Theft Auto will ever feature a female character, magazines and the press will also tell the novices: "The first title to feature a female protagonist". And again, it was already there....in the first GTA. The idea of having LC, VC and SA in one game like in GTA:SOL was already there in the first GTA. Even though I read it in a lot of blogs and online magazines that Rockstar is having that idea for the first time, when they told it in an interview. It's all nothing new.
Every GTA is just going more and more near the point of finishing a Grand Theft Auto like the first one with San Andreas, Liberty City and Vice City, all in HD with online multiplayer (wasn't there a multiplayer in GTA1 and 2? http://gta.wikia.com/Multiplayer) and additional features. They are just rebuilding it all.