I couldn't have said it better myself so I won't even bother.
Here is an essay on Tactics & Strategy in Game Design that does an excellent job of explaining some of the things I love about the way B/X is designed.
I have said a bunch of times on this blog that as one goes farther back towards the origins of the game the closer it resembles and plays like a wargame. It is many of these tactical and strategic elements that make me love B/X. And it is these elements that I discussed in my post Feedback From Some Former Northern Marches Players
Tactical Elements of B/X:
1. Resource Management - "One of the bedrock concepts of tactical play is to make the most gain with the least expenditure." This is key with the low power level of B/X characters.
2. Dissimilar Assets - "Combining Dissimilar Assets into a functional and dangerous whole takes skill and knowledge." Fighters are different from Magic-users and different from Clerics.
3. Maneuver - "Maneuver is getting the right resources into the right position at the right time in order to maximize your chance of success." Amen! Ask questions and investigate!
I found this essay through the interesting Whitehall ParaIndustries blog.