Sure it leads to more action, but it also can lead to simple minded spam, TF2 is a great example for this. Very fun if you want quick arcady action, but every phase of the map plays out in similar ways, fun for once, but playing it over and over again the game becomes repetitive.
What made W:ET so great was that the matches played on the same map could all be widely different. That’s what made the game so incredibly addictive, the only thing you could expect during the map load was that the game will probably be unlike any other time you played on that map.
I really wouldn’t want the game to feel like a treadmill, where your only option to break the repeating patterns is to change the character set up. W:ET only had a few character options the rest relied on your own creativity within the map. Imagine what a game that combines these two could be like.
The most rewarding thing about having such ‘dynamic’ maps was that tactical insight was greatly rewarded. You take the information from when you were alive, and should you be a talented or experienced player, subconciously your brain already would extrapolate this to tell you when and where the enemy would be and what they would plan to do. All this would give you a huge edge over players who only know how to point the cursor at the enemy.
I think the fear that this layer of depth, this skillset, could be downplayed in the game is a valid concern.