replacing pool tiles

[Carolina]

We have a 6 yr old inground pool (gunnite) with a raised spa and waterfall. There is a large section of tile (about 50 square feet) under the waterfall - and unfortunately, about a dozen 2x2 tiles have fallen off.

Instead of simply reattaching the missing tiles, we are considering having a tile contractor remove all the tile from the 50 squ ft area and replace it with new tile. We simply hope to stay ahead of the game and avoid having more tiles loosen and fall.

Does anyone have advice regarding this repair? Would it be smarter to simply replace the few tiles that are missing? Are we compromising our pool's integrity by trying to remove that large section of tile? Thanks for any input.