Also, you must describe, what the trap will be?
As an example.......many maps in STW have hills around the perimeter with a valley in the middle. When fighting against a Yari-heavy invader with me having lots of cavalry, I will place my infantry in the center and hide my cav on the flanks (in wooded areas, if possible, or behind a large hill). I try to lure the main bulk of the enemy towards my infantry using Cav Archers skirmishers. If/when the enemy takes the bait, the trap snaps shut and not many make it out alive.

Another example using muskets.....usually one likes to have a long, clear line of fire for muskets to bring the enemy under constant, long-range fire. But hiding them in a wooded area on a flank, then popping them out for a close-range volley is often enough to cause the unit under fire to rout right then and there. I've busted H3 monks using this technique.

I don't think that I bungled the defense. In most occasions I had poor garrison force against an elite stack.
Well, that goes without saying.....I was referring to more or less equal forces. Still, even with such a mismatch, one should be able to take a heavy toll before defeat comes...........

You can guess the general layout of the map by studying the strategic map closely.
Guess is the key word, there. One shouldn't have to guess. Too many times the scenario I previously described where I should have the terrain advantage (even on the strategic map my army icon stands head-and-shoulders above the defending army) ends up being an uphill corner assault.

And it is great to recognize familiar vistas in RTW: the layout of the landscape is realistic enough (although the scale is wrong).
I thought the same thing.....at first. But I actually like STW maps better. Or more precisely, I much prefer STW ambiance, if you will. When you fight in heavy fog or a thunderstorm, the feeling produced by the graphics trumps the eye candy of RTW. And speaking of weather.....fog, for instance, adds another tactical possibility for traps. I love fighting in heavy fog as either the attacker, or defender. Bad weather in RTW has minimal impact on tactics other than affecting archer fire and snow giving combat benefits to certain units. Heavy rain doesn't last long enough to affect cavalry stamina....and besides, most battles seem to be 10 minutes or so of marching/maneuvering and 5 minutes or less of fighting I've had monumental battles in STW, for instance, that lasted an hour and a half in real time When those kinds of battles were over, you feel as tired as all those little sprites that made up your units