"Only italic for replaceable and variable text" - I dislike the effect of the combination, but then Italic, standing alone, already has a defined role. In my opinion to give it this role as well will cause a great deal of confusion.
"extend code tag to end of entry" - I agree, but if we develop the additional tag there will be no point in starting such edits.
"kbd tag, not code, for user input" - I await Yurchor's comment as to whether, in the long run, this would help or not. I'm happy to go ahead, if he is, but his comment about getting people to follow rules does stand. We have seen a strong argument in the last week or so where a writer saw no reason to obey our rules.
This leaves us, I think, having to choose between discouraging writers or creating a team of editors to mark up every new page, as soon after creation as possible, with standardised markup. That's something of a thankless task, and I'm not even sure that the authors would accept it.
Re-formatting pages is just a waste of time (imho). Tomorrow someone can dislike something else... If there will be no overlaps we can proceed with any formatting. There are enough editors to fix articles (at least now). And I'd rather revert any inconsistent changes in markup in manuals without having at least a little hope of fixing the whole manual by the particular editor.
The consistent look and feel of manuals is better than inconsistent usage of the best markup ever discovered (imho).
I'm not sure what you're saying. Yes most people don't follow rules, but it can only help to develop the right rules. The more they make sense and are consistent with what people are used to (italics for variables, kbd as the tag for the keyboard input, etc.), the easier they are to follow.
I can live with bold and italic as your variable text rule if changing it will introduce inconsistency within your wiki. But extending the box and using <kbd> make sense, and over time the wiki will improve.
Anyone got a month or two to spare? Seriously though - since we are all agreed that <code> markup should encompass whole commands, the logical first step is to correct such things as we find them. Even if we felt it worth the time involved, there is no way that you could search for and find such broken instances, so it's down to alertness and common sense.
To be honest, I would rather not include new tags such as <kbd> unless we can see a genuine advantage to it.
One more point. Generally we use wiki-markup (with a few additions thrown into the mix) but as a rule we discourage use of HTML markup as it tends to interfere with wiki-markup in unpredictable ways. For this reason I would prefer not to introduce more HTML markup in the guidelines. Better a new template, if it is really needed.