Rigidbody Platform Character Movement

At present, I'm developing a Rigidbody in place of a character controller for use as a player object in a 2d platform game.

I've run into some "basic" problems, show stoppers as far as fluid movement is concerned.

I want my script to be simple and elegant, a departure from my last works. And I what I mean is that I don't want to program Left keys separately from Right movement. So far, I've only gotten jumping and running down.

• If I run into a 90 degree wall my character (box) gets stuck and can't jump.

• When I jump into a wall, the character sort of bounces off and on again like repelling.

• I wanted to add wall jumping. Originally, I used tags (and still do) to determine if it was a wall. (If jump pressed, and clinging = true, jump like this). This barely works. It's not fluid at all. I've realized that I need my character controller to react based on his location in relation to the platform or floor, rather than what the object is tagged as.

Ultimately, my questions are thus:

How can I script a rigidbody to know how to jump based on whats in front or below him, and,

Why doesn't the bounding box for the rigidbody prevent the character from going through objects?