So almost as perfect a form set as you can get.

Caiman is amphibious, hits for 2-4 massacre mangles, has dam redux, and has regeneration. It's an incredibly sweet form, especially when you get it at level 22.

Seasnake would be a top tier defense form if it could go on land. It's basically bobcat with better skill dodging, plus sand lizard regen, and does one poisonous DEVAS a round. You can easily hero with this form alone.

Orca is alright, I guess. Closest I could compare it to would be a water only ram, only better.

Walrus is walrus. Two to four DEMO DEVAS while in water, pachydermesque damage reduction, gore for another two DEMO DEVAs every couple rounds or two. It can also go on land. Still a nice form on land, though. Think it gets less hits, and I know for sure that the damage reduction is reduced, though not so much as to make it unusable. I'd say to around polar bear. It doesn't get extra lag when moving room to room on land, though, which is what I was expecting.

Problem with a water water shifter is similar to a ranger's problems, only worse. That is, with reduced numbers, and having to depend on people coming into the water, once you're done exploring water areas you're left with fuckall to do. I was able to clear out aboleths solo, though. If I'd had a couple periapts, I could very easily have taken the kuo toa king, as well.

Water shifter ranking is pretty simple. Planar sanctum, water elementals and water mages, then coral head/sahuagin village, then ruins of the deep. Aboleths if you have a nice enough form and want to be out of the way. If you're evil, it can be worth it to tag a storm giant or two on the volcano and have them track you down to the river to tear them apart.