The only thing that confuses me about these achievments is that there are six achivements, which have to do with stunning... However only the melee unlockable (which will be most likely the last one) can cause stunning... So there are six achievments, which you can't get as long as you don't have every milestone...? Seems a bit much for me... I mean every other class update had only like one or no achievments, which required the last unlockable... Meh... maybe the new Scattergun's knockback counts as stunning too... oh well... we'll see.
indeed! I like how they tell you what the plus and minus of the weapons are by the way, on the bottom of the page, you can vote for which weapon you want to be the first unlockable.