No, you should be looking for a more appropriate surface to apply the tile to in a difficult environment.
Taking off the sheetrock and putting up cement board really isn't that big a deal. Very easy, in fact. Here's what I would do...
- Remove the drywall
- Staple 30# building paper all around on the walls in a shingle fashion; i.e., start at the bottom, wrap around all walls with ONE piece, keep going with additional pieces until you reach the ceiling, lapping each piece 3-4" over the one below it, covering the nails/staples. You wind up with one vertical seam so take another piece of 30# and apply it vertically lapping the seam by 6" or so on each side of the seam.
- Put on the cement board. Where two walls meet, leave enough separation between the pieces of cement board to pack in a bead of silicone caulk. You want the caulk in just the seam, not on the board.
- Apply the tile with thinset.
- Grout the tile
- Seal the grout
Do the above and your shower is going to last a long, long time. The grout in the corners where two walls meet is going to crack; NP, there is caulk back there too...and if that ever failed, the framing is protected by the
30# felt.