Ahem OP - At 1:50 I talk about the expertises, classes (specializations) and point out that all it affects is the gear:

@Megapull: Will expertises somehow impact the character in the final build?

Here I'm thinking that a melee focused crusader would gain extra benefits from using melee weapons/shields (+10% bonus for instance) over the other Crusaders. A Heavy crusader could have his movement increased when carrying Heavy weapons to illustrate that he has trained specifically with these kinds of weapons and the Gunner could be adept at firing the aimed shots of weapons so he would have a higher chance of shooting off limbs than other crusaders.

Instead of it just being the starting gear, it would matter to some degree what you chose. It could also be that one or two weapon types were restricted for anyone BUT that expertise, for instance it could be that heavy crusaders were the only ones that could handle the Heavy Flamer.

Adding meaning to the specializations is important in my opinion.