Maybe different people have different conceptions of what makes for a meaty campaign with an epic feel.
One thing I've found over the years is that if every decision comes back to tactical expediency, then that will tend to undermine the epic feel, and push towards some sort of "shades of grey"/gritty/special ops vibe instead.
Another thing I've found is that the best way to avoid every decision coming back to tactical expediency is for the GM to create a "space" in which non-expedient decisions do not end up biting the players. For example, let players extract promises of repetance from prisoners and then have prisoners keep those promises.
Whereas I find that strong use of mechanical alignment tends to undercut epic feel, in part by shifting the focus away from the players' choices and decisions and back onto the GM's own evaluative judgements.
In DnD if you are playing save the world from great evil style of play which we are. Then it absolutely becomes part of playing tactically wise if you fail it is not just you who die it is the entire world.
Part of the fun at least for me and most of the people I play with is making the choices even the hard ones. Getting away from the kill evil clerics for a moment say you are heading to stop an event that will happen on the full moon it is two days to get there and if you ride hard you can make it in one.
You come across a village besieged by orcs. You can A sneak around and make it in time to stop the event or B you can help the village and take the chance of missing the event. It is a tough choice and neither is really the right answer. Some players may choose to save the village from the immediate threat and hope that they will still have time to get to the event. Others may choice to leave the village to its fate on the idea that saving more lives is the right thing to do.
To things like this can make for some compelling role playing. With the right players and the right DM.
And I disagree that you can't have an epic game that sometimes has gritty choices in it. I also disagree that alignment makes this impossible. It depends on how you use alignment it is a straight jacket, is it setting specific, how does the DM define it.
I am not advocating always taking the best tactical choice and killing the prisoners but I also don't buy the never ever under any circumstances kill the prisoners either.
In the situation I described we were far from any help. We still had two more evil temples to deal with. We were outnumbered and here were our choices leave and take the prisoners to a high authority which would take hours which gave the other temples that chance to find out what we had done and be better prepared for us when we came back.
Tie the prisoners up and hope they didn't escape to raise the alarm. Try and drag them with us and hope they didn't give us away and which would mean one of us keeping an eye on them instead of being free to do other things.
Or kill them. Tactically the best choice was to kill them. Though not everyone agreed. The fun part of the game to me is dealing with these choices.
And not once did the DM interfere in our choice. We did talk about it later and she did say that if we had kept them alive she would have rolled escape artist rolls on them and played them in character which was to stop us. But she would have done it fairly by the rules and the roll of the dice.