It depends on the title(s) - some titles are definitely using >8GB RAM, depending on the settings.
That board I suggested only has 2x DIMM slots so, in the event you opt for 8GB, you'd probably want to go with 1x8GB to allow you room to upgrade in the future *BUT* then you're giving up the benefits of Dual-Channel for now, and there's no guarantee an additional 1x8GB in future will just "work". RAM can be quite a pain when you attempt to 'mix and match' modules that were not sold together in a retail kit.
tl;dr. Bottleneck, maybe. 2x8GB is going to be easier in the long run.