Assuming the SCAR doesn't suck (it's a new design, after all...one needs to be cautious about assuming it does everything it is advertised to do), is it better than a FAL? Probably, yes.
Depends on your version of better. Only thing I see "better" about SCAR is the ugly stock that has an adjustable comb. That is a pretty good idea for optics users.
Better to me means parts and accessories availability. Can I get spare bolts, spare barrels, mags, firing pins, spring kits, furniture, etc etc without having to auction off an arm or a leg? I can with FAL. I doubt SCAR parts will ever be widely available with the exception of directly from FN.
Accuracy: FALs have a hit-or-miss (ha!) accuracy potential
If there were millions of home built SCAR kits, Century SCAR builds, etc then your point might have more validity. If SCARs were contracted out and manufactured round the world in many different factories to slightly different standards then maybe it would hold more water as a legitimate advantage.
Good STG-58's are 1.5 moa capable, which is accurate enough to fulfill the DM role that I am assuming the SCAR was designed for. If the SCAR is 1moa capable, great, but .5 moa doesn't seem to be much improvement for a DM or minute man role.
Subjective as you noted.
Weight: It's lighter. Nuff said.
The extra weight is near meaningless to the civilian user. I'd rather the indestructible steel parts of the FAL than the small weight savings gained by substituting those same parts with plastic in the SCAR.
To me the worst part of the FAL is the sights, which just ain't all that. They function and that's about it. I wish there were better irons for them out there. Still, I have found them completely usable.
Assuming the SCAR doesn't suck (it's a new design, after all...one needs to be cautious about assuming it does everything it is advertised to do), is it better than a FAL?
Well, in fifty years when the results are in and there are SCAR kits everywhere for $129 bucks and receivers for $175 bucks and whole forums develop around the mystique of the rifle and countless foreign armies produce or procure SCARs by the millions then I think we'll be able to draw a conclusion. Seeing as how it's brand new and basically a "refined FAL" I think it has shoes too big for it to ever fill.