In a forum conversation, someone brought up the idea of allowing some bonuses to stack in order to encourage "tactical thinking". I responded that I was opposed to that, but I've already discussed that here. What I want to focus on why I don't think of "bonus-mongering" as tactical thinking, and why I think you can have tactical thinking without knowing any bonuses at all.
Let's start with the coup de grace rule, mentioned in AD&D, but still pretty common as a house rule in OD&D and across all editions. A sleeping or helpless (bound) opponent can be killed with one swift movement. There's no attack roll. There's certainly not a +8 bonus to hit sleeping characters. It's just an automatic kill.
Then there are doorways. If there are a lot of monsters, you can try to maneuver to where they have to pass through a doorway one at a time. If there's room for warriors to stand on either side of a doorway, and one warrior in front, the monster passing through the doorway can only make one attack while being subject to three attacks. If that's still too dangerous, but the monsters are in an area with no other exits, you can try slamming the door, spiking it, and possibly pouring oil under the door and setting it alight.
If you're being chased by a monster that can't climb, you can climb up to a vantage point, if you can find one, and then attack safely from a distance.
All of these things are tactical decisions that don't involve knowing anything about the game system. You don't need to know the numbers related to these things, only that being in a position where you can attack and your opponent can't, or where you and your buddies can gang up on one opponent at a time, or where you can control your opponent's movement, are all good things.
This is real tactical thinking.
The other kind of thinking is really more about optimizing attacks. It's focused on the game rules. The problem is, some games (like OD&D) don't have many bonuses, or much difference in the bonuses available, and might not allow bonuses to stack... and the solution, to some people, is to add bonuses so that players can "think tactically". As if they couldn't do that without a rich supply of bonuses.