Water forms are as good for exploring as having a souped up utility form. They are similar in that pound for pound they handle themselves in melee better then most other forms. They of course still have the same draw back as any shifter solo exploring without a regen form, you are going to have to rest up a fair bit.

The whole half the mobs are immune thing has been changed since they un blunt immuned tons and tons of mobs.

I mean even though they might not be the instant I win button every single high level underwater area (a lot of the tougher ones have casters which can be rough on non regen forms)if you get a buddy that is a bard, healer, invoker, well anyone to be honest you can do some serious damage. You are likely to be so strong both offensively and defensivly that a lot stacks well with you.

Then again I have never had a regen form and done plenty of succesful shifters it certainly takes an amount of patience but not having any regen forms at all is certainly not the end of the world, you do get slow as a class spell.