Well, there is no need for secondary professions when each profession is meant to be able to do a decent range of things already. Pre-selected weapon skills are good because they are easier to balance, making it harder to put together a skill set that is just bad. Guns own and are a natural progression of the blackpowder and cannons that exist in the first game, over 200 years prior to the sequel. The thief is a decent, generic name for the hit-and-run sneaky class with the added bonus of really being able to steal things. Not that you have to be interested in every class to play the game. I don't care about the ranger or the thief but there are other possibilities.
On the whole it looks like they are going to make the game play superior to GW1 in basically every possible way. I have no idea how well they are going to pull off organic events and so on but it's quite a lot more ambitious than the first game. Based on the strength of the ideas shown so far they deserve to succeed at it.
Your nausea isn't something anyone here can do anything about. Sorry.
Check back in a couple of months, I guess, or when the beta starts. We'll really know how things work then.