Does GOG will work on famous RPG "old School" Games like :
To mension two series:
- D&D Gold Box Package (with a good work on the journals to improve the gameplay)
- Final Fantasy Series (mainly all the series which was most for Console players)
I am sure lots of people will be ready to pay for these ones with a good work on (like other gog games)
Thanks for the advice.

Nothing is known about future GOG releases until a deal has been made with the publisher, and they are officially announced and put up on the "coming soon" list.
If you want to (arguably) raise the chances of a game you like to arrive, please see the wishlist and vote for a few games. The game probably exist in the list already (and even multiple copies of it, with various misspelled titles), but if it doesn't, you can add it.

There's a good chance I'm mistaken on this but I think -- as far as the Gold Box series goes -- they are sort of in limbo as to the current rights holders. The original publisher SSI went bankrupt/was bought out a few times and the titles now rest with Ubisoft. Not sure if they've attempted to sell them since.

Unless Atari have/buy the rights to gold box games then there's no chance of seeing those anywhere. Never mind here. As there is also the issue of Atari not being on GOG...

One thing about your requests though. If GOG does ever get the games they won't change the game play AT ALL, if it can be avoided. Keep in mind the only things they'll do is make them run on current systems, they won't even fix the most minor of bugs unless the original owners of the game release a patch for it.
*(This is in response to your comment about the Gold Box games)

FYI, there's a shovelware goldbox comp.
It's called "gamefest". Check ebay. I purchased my copy a while ago for <$20 (USD).
http://www.mobygames.com/game/gamefest-forgotten-realms-classics

Thanks for the comments.
I will check the Wishlist !