I have a shower stall with sliding doors. The shower head is opposite from the sliding doors. There has been a leak showing through the ceiling of the room below, and a plumber has told us that this is because the flow of water against the shower stall doors is too direct and causing the caulk around the basin to deteriorate, resulting in the leak. He recaulked the basin and has advised that we hang a shower curtain inside the stall to prevent this from happening again. He also said the head should not have been installed opposite the door, and the only other option is moving the shower head so that it does not face the doors. I am thinking that if properly caulked, there should be no need to move the shower head nor hang a curtain. Could you give me a second opinion?

If the water hits the sliding doors it can spatter between the panes, I don't think your caulk is much of the problem. Caulk doesn't deteriorate from getting wet. How about adding a flexible handheld shower head that can lift out if its cradle and be directed at a soild wall. Cheaper than moving the plumbing and nicer looking than a shower curtain inside a glass stall.