To me the FX2 Chains represents an opportunity for creativity. (If we had more than 6 knobs/buttons)
There's thousands of combinations of different effects that could be thrown together with an easy clean interface, spend time and make the effect once, and then slap it on a track every time you need that again, and if it could mimic number of ACT controllers, total intuitive control.l
Or.. how about those hideous GUIs many effects have where they try to mimic some real hardware with gaudy graphics (And fail miserably, only to break every interface standard because their custom made GUI doesn't follow any conventional standard, no tab order, common UI element shortcuts are broken etc..), just wrap a FX2 chain around that and forget the GUI abomination ever existed.
And lastly, an opportunity to wrap every plugin you use into a FX2 chain, place things in the order you want, not what the plugin creator wants, and have everything look the same, clean and efficient.