When H&H first came out, the water walking perf tanked the FPS massively - like down to 3 FPS, and at first the only solution was to take one's pants off. This issue was reported by a few people over at Nexus and the FPS hit was identified and fixed, but the actual water walking ability itself still doesn't work. Guess we're waiting on RandyKnapp.

I used to use the perk myself in the past and I ended up forcing myself not to because it killed one aspect of the game - I found it absurd being able to run across oceans, but each to their own