I think it would be too reductionist to equate the physical, observable world to God and close our eyes on the possiblity of anything else that could lie beyond as so many pantheists are doing nowadays.
If the Universe as a 'soul', if it is alive at all, if it has a purpose as it's governing dynamics suggest, then it must be the manifestation, realization of another and perhaps grander principle which we know nothing about or are simply unaware of in our (very convincing) illusion of concreteness. Hence, Panentheism seems like a much more reasonable position to me, as it takes into account every possiblities that the human mind can account for, acknowledging that the Universe/Multiverse is in fact 'God' but probably not the whole of 'God'.