So, make sure your game tries to cater to everyone's preferences to ensure you all have fun. Having fun is a key to feeling rewarded for roleplaying, and so is success. I'd make sure all group efforts and plans were met with almost overwhelming complications. And every success was tainted with a secret hitch. I've learned, as far as my game style goes, and perhaps this suits your group's style too, that it can be just as rewarding planning things as it is doing them.
Planning is like a puzzle.
It's problem solving. However, if you reward every good plan with failure then your group will learn planning is useless. If the players have just spent two hours bickering back and forth in-character, tailoring a solid plan, I'm going to let it succeed. To me, that's equivalent to a two hour combat encounter, or a two hour difficult puzzle encounter. It's good gaming.