While I agree with this, I have an Intel graphics version of the T430 (running Ubuntu) and it doesn't seem to play nice with two external monitors, even with the "fully loaded" docking station :(
I had external display issues as well, with a T440 and an UltraDock under Debian. It was mostly flickering and blinking of the outputs, but occasionally a display wouldn't come out of powersave mode.
You may have already found and tried these possible fixes, but just in case you haven't-
1) There's a firmware update for the docks that is supposed to resolve a number of display issues.
2) It appears that similar issues can be caused by having a defective or incorrectly-sized dock power supply. So replacing the power supply with a known-good and/or bigger power supply might help.
Though, in my case, neither of the above helped. It turns out I had a bad HDMI/VGA adapter. Since eliminating that, I've had zero display issues. But I'm guessing that probably doesn't apply to you, since my configuration is a little unconventional.
Anyway, I hope you find something that fixes it for you.
