So to let me sum it up (seeing if I got the problem):

You are gaming for 10 years, regularly with a group of people that think the Alignment good means "Murder Hobo". People that want a more Beer and Brezeln Game.
Characterideas/builds that were non-standard (for them) are deemed either OP or outright banned. Also no real Roleplay just Hack'n'Slash.

Just out of interest (as you mentioned Saga) how fast did they accumulate Dark Side points? Why doesn't their alignment shift to something more fitting?
What is the DM's point on this or do you have rotating DM's?
Why hasn't there been any In-Party conflict in basically the first session? I would think your characters would get big problems with it, or wouldn't they?

I get the "Shoot first, ask Questions later" mentality as it is a reasonable thing that could develop as an adventurer. But as you said maybe you just want other things out of it. IF you can really find another game or another group then maybe this will work. They will have their more railroady games and you will have a group that is more in-character.

That is the thing (which makes this hobby the most interesting for me), the diversity in what ways you can play. Rules light, just hack'n'slash, intrigue, character in-depth development and so on.

I would say: talk with your group again. Adress your problems and tell them that you plan to go as your playstyle conflicts with theirs, then see what reaction you get and act accordingly.

Good luck.