If a view falls short with respect to the main doctrine it's organized around, that view is seriously flawed. For instance, if Calvinism fell short with regard to sovereignty, it would be seriously flawed. For pantheism, the relevant doctrine is omnipresence. On its face, pantheism is designed to make omnipresence work out perfectly: if God is everything, then he is where anything is.
But is that enough for omnipresence? First, perhaps omnipresence should also imply that God is in the places where nothing other than God exists—in otherwise empty space. Whether pantheism can account for that perhaps depends on whether it's deflationary (God is nothing but everything) or inflationary (everything is God, in addition to what it ordinarily is, and there may be more to God than ordinary things—and hence in particular God might be where there is nothing ordinary). That said, perhaps this is not so serious. If substantivalism about space is false, then maybe there are no empty places, except in a manner of speaking.
More seriously, by making God be everything, God comes to be only partly present everywhere. Only a part of God is in this room where I am—a very small part and, at least on the deflationary variant, a very insignificant part. Yes, God is in the stone and the butterfly and the galaxy—but all of these are very small bits of God. Classical theists, however, have the doctrine of divine simplicity and so we can say that where God is, all of God is.