Just about everything I can think of would fall under 'long-term strategies' and you don't want those, so how's this:
A fully fleshed-out all-direction and preferably setting-neutral conversion guide covering all major elements of the game through all editions - yes, that includes 0-B/X-1-RC-2-3-3.5-4-Ess-5; the use of which would allow someone to take element x from edition y and easily and seamlessly convert or adapt (or adopt) it into their edition z game. Ideally, this would allow one to convert a 5e element into 2e just as easily as converting a B/X element into 4e or a 3.5e element into RC.
Want to put 1e weapon-vs.-armour type rules into 3e or 4e or 5e? Here's what to do.*
Want Dragonborn in your 0-1-2e game? Here's how they'd fit in, complete with racial level limits.*
Wnat a 4e skill system including skill challenges in your Basic game? Follow these steps.*
* - always followed by a quick review of possible knock-on effects and-or other required/suggested changes likely arising from this change.
Yes, this would be huge...probably several volumes...but I still want to see it done.
Lanefan