People often say "even if you don't respect the man, respect the office", referring to the President. Do you think this should be codified?

While correct in my opinion, this saying should be interpreted very carefully. The President should be respected only when he is representing the nation. At major national ceremonies, the President should be shown the respect of his office, and not (for example) interrupted by protesters. But when engaged in political operations, he is just another politician and you should be as free to express your opinions as with any other politician.

How can you codify respect?

I was brought up having total respect for our President but that was before the President represented the party or special interests instead of what was best for the country. If the President deserves it, take your best shot.

No, it would give the president an unfair advantage as an incumbent in his second election.

Also it would be unconstitutional as per the first amendment.

As much as we dislike what certain high profile people on TV are saying, especially when it seems like the president is damned if he does and damned if he doesn't, if we deny them thier podium, they would have a legitimate reason to take up arms.

You should ask about filibustering and the republican's obstructionist tactics. (70% of bills being filibustered compared to 25% or 30% [at most] in the past)

If you ask me there should be a percentage limit on how many times you can use the filibuster, or you should be forced to talk to stall the bill like the old days.