If you're willing to change the way you think a bit, I would recommend FATE Core or even the FATE Accelerated Edition. Both are "pay what you want" in pdf form from DriveThru, etc. (meaning you can legally download them for free, if you want).
Personally, the Fate system has become my "go to" gaming system, especially when I have an idea that I can't figure out how to immediately translate into another game. It works for me because it's focused more on a narrative approach to gaming using Aspects (short, descriptive phrases) to describe character abilities, personalities, backgrounds, etc. Aspects are also used to describe scenes ("Dark and Stormy Night", for example) or items ("This Was My Father's Lightsaber"), rather than crunching numbers, min-maxing, etc.
It can take a little getting used to if your group is mostly used to killing things and looting the bodies, but it's actually pretty user friendly overall. Definitely worth a look.
But yeah, it doesn't really matter what system you use if the players just want to roll dice and kill things. You might need to have a "round table" type discussion with all of them and just say you want to step outside the box for a little bit and try something different. If you think they'll be really resistant to the idea, pitch it as a "one shot" game or brief series of two or three sessions and then make sure you have a really cool premise that they won't get bored with. That way you won't need to lively it up by throwing in the obligatory fight scene.