My only concern is that if it was accepted nothing would happen for either side, and will just provide more ammunition for atheists.
Christians are too influenced by incorrect theology and corrupt interpretations, especially by the name it and claim it crowd. Yes I can pray to GOd to bring fire down or whatever to prove his existence, but GOd proberbly will not.
Elijah was a one of the few special people on this planet, he was chosen by and anointed by God, he had a very special relationship with God and had reached that stage where things he said happened all of which would have been directly influenced by God.
Elijah knew God would deliever on whatever he did in his name, can Keller claim the same thing? Is he in that special spiritual place where God will do that? I do not think so.