Of course I had to look up Wittgenstein. It seems that he went through 2 phases that were quite incompatible with each other. You are mostly talking about the first phase while I am more sympathetic to his second phase. I can understand why you would object to a concrete God based on Wittgenstein's phase 1. But it seems to me that Wittgenstein's phase 2 in fact justifies a concrete God as a kind of language game.
I am playing by your rules here when in fact I simply reject all of Western philosophy as I explained in my "Truth and Alternatives" post.
Just speaking practically, I do agree that an abstract conception of God is less problematic for intelligent people. But for stupid people, there is no question that a concrete conception of God is more effective. A successful religion must address the full spectrum of human intelligence. Islam does this by elevating Muhammad and the prophets. Intelligent Muslims can think in terms of God while less intelligent Muslims can simply focus on Muhammad as a means of relating to God.