I think this would need to be done in 3D, I've tried some similar things, like I did a letter text exploding into tiny balls, doing wataer drops is a bit more involved but can be done in an app like 3ds max (or other comparable 3d app) as far as doing it in after effects, I think it may be possible but I'm not sure how much control you would have over the look of it also considering that with water it can be hard to get it to look right without using an environment map on it (in the 3d application) for the reflections since without proper reflections and lighting water is just clear and usually keeping it just one color doesn't look realistic
I guess what I was think, to be more accurate, was text functioning like drops of water. So they would drip from the top and fall to the bottom with the typical water drop form at the bottom and the typical tail stretching out a bit behind. But the form would be the text itself, not water.
Do you still think about would be better done in a 3D program?
I'm having a bit of trouble envisioning what you are describing but it sounds like this is something that would be suited for particles in a 3D program... for example, you can take text in the software and easily convert it to particles (which can be made to look like each letter is a droplet of water)... actually you could possibly do this without even using particles and just using displacement which I believe after effects has support for (not sure if you can import your own custom displacement maps) but you can use a displacement map to make a solid object look like water although it'd probably be hard to do for a droplet as its more suited for something like a pond, river or ocean (with the ripple / wave displacement)