Many intelligent people have been, and are, religious. So, the former should not be precluded by the latter. But, does the latter preclude acceptance of certain kinds of religion, over time?
To use one example, there must have been something about Christianity which accounts for its engulfment of the Roman Empire and dominance of portions of the world, and history, for such a long time. There are those who maintain that its early success is the result of its absorption of aspects of various popular cults prevalent in the Empire, and that its later success is similarly based on its ability to incorporate characteristics of local customs and beliefs (through saints, for example)into its system.
Certain aspects of certain religions, though, are naturally fantastic or become so with the passage of time. God becoming man was not necessarily an unusual idea in ancient times. However, it's something that would not be expected by most these days. Similarly, religions based on images, customs and language of those living thousands of years in the past, in very different societies, may be expected to wear out over time.
The less convoluted the religion, the less dependent it is on images, customs and beliefs which are themselves tied to particular times and societies, the more likely it is to withstand challenges. Thus, the impersonal "God of the philosophers" is more acceptable in the long run, and less subject to attack, than the anthropomorphic Gods of most organized religions. Is such a God therefore more believable--more worthy of belief--than others? Perhaps, in the sense, at least, that it is not as open to the criticism that it is a purely human creation.