A bunch of janitors had a long conversation about this earlier today in IRC, and there seemed to be a general consensus that something should be done, but also a consensus that it's a complicated issue. Several people (including myself) think the GameBoy Advance should be allowed while still not allowing sixth-generation home consoles. The GBA is decidedly old and retro: it has a defunct brand name (GameBoy has not been used since), a tiny resolution, and very little capability for 3D gameplay, and the games made for it cannot be played on any console or handheld Nintendo currently produces. Meanwhile allowing the 6th gen consoles would open the board up to a lot of flack, and allowing one or two of those consoles would make it seem even more fair if we (in a reasonable move) exclude the PlayStation 2. I would suggest one rule for handhelds and one for home consoles, but that could chafe people pretty hard.
On the PS2, it really is the big problem (in my mind) that still exists with that proposal and with moving up the date and a lot of the ideas for fixes, because it had such an unusually long and fruitful life. If we go by the standard of allowing titles produced after 1999 for systems made before 1999 then we'd have some games from as late as 2014-- that's really stretching it of course, but there was a good flow of games for the system through the entire first decade of the 2000s.
Additionally, there are concerns that opening up the GameCube and Xbox to the board would open up discussion about Smash Bros. and Halo respectively, which are ongoing and popular series and are largely defined by more recent titles. I don't see that being too much of a problem outside of designated shitposters and people who lack the sense to grasp some rules anyway, but it's worth looking at.
I would suggest allowing the GameBoy Advance and its entire catalog, along with allowing PC games made in 2000 and 2001, with the 6th gen consoles to be allowed around 2021, at 20 years old.