Dragoons - I don't see too many of them in the high end content

[Vodomir]

Is it the games fault a lot of Dragoons and Monks can't dodge tail and side swipes?

To a certain degree I'll have to say yes. Why do you see more DRGs and MNKs being hit by tail and side swipes while magically each and every ranged DD doesn't get hit at all? It's because those tail and side swipes only happen in melee range. If the ranged DDs had to dodge the same thing, they'd be making the same mistakes. It's not like ranged DDs are better players because they play ranged.