I'm planning to use both cameras actually dipending on level the player will be playing his character differently.. from exploring to stealthing to fighting. That means I use different player's actions (script).
That matches different types of gameplay experience all together

As for collision.. the scripts need a better tuning as well as the character model and its animations..
Once again guys.. I've been working on this by myself so I couldn't afford to take care of details. One of my 'dreams' would be working with a partnership at least and take care of 2d/3d arts while a professional programmer would do the other job. I'm cool with design, cause it's been already studied somehow.
Well waiting for more responses anyway, so thanks again for your replies.