Case in point: vimium only works in chrome by loading a custom javascript file (basically how all chrome extensions work). Which means if a page errors on loading, that tab doesn't get vimium bindings. Which is quite annoying when flipping through tabs, only to stop at the error'd tab and have to use the mouse to get off that tab and continue flipping.
I agree that this is annoying, so instead of using the vimium tab-switch bindings I use the standard chromium tab-switch keyboard shortcuts (no mousing is necessary)