I'm similar. I'm playing a lot of Terraria recently, and it bugs me that you can have a tower of water in a tube connected to a shallow lake, and the pressure doesn't force the water through.
That bugs me too. I have started a small project to make a more realistic water simulation, and found it to be quite a bit more involved than I had expected. Just adding pressure would fix the problem you mentioned, and would probably be pretty easy to do. Adding velocity so that the water sloshes properly seems to be the hard part.
fluid dynamics is anything but easy. current sandbox games (minecraft, dwarf fortress, terraria) implement water flows as cellular state machines. this is clearly wrong, because pressure is non-local, but computational expense of doing water correctly is prohibitive.
> current sandbox games (minecraft, dwarf fortress, terraria) implement water flows as cellular state machines. this is clearly wrong, because pressure is non-local
Dwarf Fortress's algorithm actually supports global pressure propagation, albeit in an ad-hoc fashion:
There are some mods that try this. Finite Liquid (http://www.youtube.com/watch?v=XlnUXXzc1Fg) for Minecraft, for example, implements a simple pressure system, along with pipes, pumps and other flow/flow-control tools.