Thank you for the feedback all.

On this picture you can see it's not a straight top down perspective. Otherwise we couldn't see the windows on the house, we would see only the roof.
It's quite nice. However:
- all the sprites look very tiny and you can hardly see anything apart from the top of their helmet or hat
- each sprite had to been drawn in four directions, as far as I can see
(with 9 player races, 9x4 pictures would need drawing just for the player characters, and that's without animation or gender differentiation)
- all the sprites have to be drawn in that not-quite-straight perspective
With a flat portrait:
- you can differentiate monsters by their face, for example an orc leader could have an eye patch and big teeth
- no need to draw in four directions, so a big sprite is ready to use after drawing it just once, and there can be more variety in the enemies
- no need to pay attention to whether the sprite respects the background's perspective
To me, the most important things are the tactics, the level of challenge, and interesting dialogues. That's why I love ADOM even though all the monsters in that game are represented with a coloured letter. Switching to flat portraits (tokens) can be seen as a step backward but it has clear advantages (big monsters & more variety in monsters).