Since when does the amount of GRAM determine the overall performance of the gfx card?
Where is the GRAM frequency? GPU frequency? For starters.
Then you have, pixel/vertex shader versions etc.
Don't turn LFS into another NFS/CoD/etc serries, where each year you get better graphics(HELL YEAH!), the same old story(MEH, BETTER GRAPHICS!), maybe just slightly altered story with some new stuff that are fun for a few minutes(STILL, BETTER GRAPHICS!).
The graphics look good enough and with lower textures etc. you have more potential players. Not everyone of us have the money to buy 500core cpus with 10 gfx cards in sli mode you know.(A little bit of sarcasm there)
As for the wanting for LFS gfx improvements over use of multi-cores. Is your gfx going to do the simulation computations when you're on a full grid instead of the other cores that are doing "nothing" when you are playing LFS?
Instead of better graphics and new content I'd much rather see some improvements to the sim, like water/oil temperature, brake wear and brake temperature etc.