The real problem is on small netbook screens, like mine 1024X600 and the first installation screen won't fit.
For some people that will mean they won't/can't proceed, mainly because they don't know how to get around it, like dragging the task bar out to the side and knowing how to use the tab key to move focus to the unseen Continue button.
So there are many screens that require the ability to be resized, be that smaller in the case of the installation window and larger in the case of some others, but fixed sizes are a poor choice.