Well, I know that beside the class system you can also opt for 'classic' worms, where all the worms are equal.
And also, the weapon panel is the same for the entire team (so not like the classes in wormpot), it's just that some worms know their way around a weap better or worse cause of their physical/mental capabilities.
For example, the fat one hitting the tiny scout with a baseball bat will send the victim a looong way. The other way around (small hitting fat) will be nowhere near a homerun.
edit:
Bit more detailed information on the Scout for you.
Advantages:
Infiltration: The Scout is great for infiltrating enemy dark-side bases! The Scout's fast walk speed and small size makes him ideal for quickly reaching the heart of bases and beating a hasty retreat if necessary. The Scout's small size also allows him to squeeze through the narrowest of tunnels.
Dark-siding: The Scout is a good class for both dark-siding and anti-dark-siding plays. The Scout's extra speed allows him to dig further than other worms, meaning he can create more complex tunnel networks as well as reach them.
Collecting: A fast movement speed, coupled with a longer and higher jump makes the Scout ideal for collecting weapon crates. The Scout can cover more of the landscape in a turn, as well as access those tricky to reach areas.
Crossing Pitfalls: The Scout's movement attributes make him an ideal candidate for crossing mine fields, negotiating hazardous objects and sneaking past Sentry Guns.
