One of the things I noticed with some of my packs is that long class names fail to display properly on the class select screen! They go off of the button and look really weird. Red Orchestra 2's class selection screen has plenty of room for class names (example: Flamethrower Operator), so I decided to make an ugly GUI in Paint.NET:

This picture shows:
Class selections. There could be a scroll bar if there are more classes available.
Class loadout. I selected the Grenadier class. On the right side of the screen, the loadout of the Grenadier is shown.
A map. This could either be a Minecraft map or a .png file created by the map maker.
Flag selection. A and B are available, so they show up as light grey. C is neutral, so it shows up as a medium grey. D and E are owned by the enemy team, so they show up as a dark grey. Use either a check box or a highlight to show the selected spawn.
A spawn button. It should be greyed out if:
-A class isn't selected
-A spawn isn't selected

Here's a version without the map:

It's the same thing, but without a map.

Looks great, would love to have this implemented.