2. I only use it when I'm out of melee range as it does reset your melee swing timer (which could effect your DPS and rage gen). There is a macro that can minimize the swing delay, but I'm not sure how many other people use it.
3. No. Intercept gets you to the boss sooner so you get more attacks in. Definitely worth the investment.
4. No. I only use Victory Rush as a GCD filler. Don't delay any of your normal attacks for Victory Rush. It lasts quite a long time too (especially with the minor glyph) so I don't think you'd need to open with it.
5. I execute when everything else is on cooldown, there isn't an instant slam proc, and I have a *ton* of rage. Hitting execute too often on a boss can sometimes muck up your rotation if you find yourself rage starved... so I try to use it only when my Rage is above 80 or so. FYI, I'm glyphed for cleave, not execute.
My .02 on execute range. execute hits harder than Slam!, but requires an abundance of rage. Use it when your safely over 60-80 rage and keep up with your regular roation. Just replace Slam! with Execute. Other than that, you are pro.
edit: name switch lawlz and fail on pronouns and sentence structure.