Hi, i would recommend you something - instead of blaming Maya's tools, to find a computer with installed Unlimited version and to take a look what exactly is going on there.
If you give it a try i think that in most cases you will notice that the fluid solver is very well implemented in Maya and cooperates with the rest of the stuff really nicely. It is not a closed system.
In addition to the regular fluid simulations you can do and things like that:
FluidContainers can be used as force fields for particles, rigid bodies, softBodies, cloth, hair/dynamicCurves, paintFX strokes, etc., or to be affected by most of them.
Fluids can be used to texture geometry ( every geoShape intersecting fluid can be colored, or directly textureMapped via HyperShade ).
You can substitute the particleCloudShader with Fluids and you can control them on perParticle basis ( pretty mutch like AfterBurn for 3DS MAX or HyperVoxels for LW3D ).
Using MEL you have perVoxel control over the fluidContainer - you can query and control every single voxel cell.
Also, there are 2 other types of fluids - oceanShader and pond. The ocean shader is really neat stuff - can be affected by particles or whatever to create effects like ripples, wakes, etc. Also the same can be done using fluidContrainers ( exploding fluid can affect the ocean surface - just an example ). In fact the oceanShader can interact with almost everything containging UV-data and shaders.
The pond is some kind of fluid + springs - very interesting beast.
The rendering of fluids is really fast - if you know what are you doing you can have almost realtime rendering of your fluids ( here i mean only gas and clouds stuff, the ocean shader is far from any realtime rendering ). Somehow MentalRay renders them faster than Maya Software Renderer.
And last - the rendering quality is really great.
About the MEL hacks - i really would be glad to have more MEL control ( hacks ) over the fluids, now they are pretty mutch only compiled code

and i really dont like that.
When we talk about MEL hacks - good one is the ability to use bitmaps to control your fluids - colors, velocity, density, etc.
I know that my post will not be well accepted here, but i have the feeling that many people are missing the essence of this Maya tool. Why that please accept my words like little heads-up, not as offense.