IMHO, no. The 308 is a lame duck. (*puts on asbestos pants*... OK flame away). OK, I know the 308 gets the job done, and it's more than a match for a man... but, all else being equal, it is ballistically inefficient (for the purpose at hand). In its current rifles the 308 wastes a lot of energy. In short barreled rifles velocity is lost as much of the propellant winds up as a fireball in front of the muzzle. In longer barreled rifles, the bullet has energy to spare. Its heavy, the rifles shooting it are heavy, and it generates a fair amount of recoil. Also, its bullets have poor BCs and SDs. When compared to some of its peers, this results in more drop and drift, but with less penetration at a higher price paid in recoil. Sure in the US it seems like the end all - be all, but when looked at objectively you cannot deny that there are better alternatives.
In my view, what we really need is a completely new cartridge. Lets stop worrying about what will fit in an AR15 or AR10 or some other platform and design something new (or make an AR in between the AR15 and AR10) Something somewhere in between the 223 and 308 length, but in 6.5mm or maybe 7mm. Over all length for 223 is about 2.25" and the over all length for 308 is about 2.8". What if we designed a 6.5mm round from the ground up with a OAL of, say 2.5" pushing, say a 123gr bullet at 2600fps (say right between the 6.5Grendel and the 260 Rem), it would have more than enough thump for 2 legged varmints and it would do it (I think) with much less recoil than the 308 in a lighter rifle with the ammo weighing less than a 308. Also, because of the 6.5mm's high BCs and SDs, it would retain velocity and energy and have great penetrating potential... But thats just my thoughts....