I’ve got a few thoughts but I have not played Draw Steel however I have read it.
What are the themes of the campaign? What do you and your players like doing in heroic fantasy?
I get a feeling from the proposed changes that there is some enjoyment of the tactical combat, as well as the superhero nature of more heroic fantasy as opposed to gritty fantasy.
The mana change would cut down on book-keeping at the expense of potential balance not only around combat but also the gameplay loop of combat - rest - non-combat encounter - combat.
Have you considered Lancer style initiative where the players go first, you go second, and then repeat until combat ends? No rolls needed, just the players to decide who goes first.
Are you going to use the automatic hit rules from Draw Steel or keeping the swingy to-hit of a d20 attack roll?
Is character death important at all?
While the Dying/exhaustion is interesting it seems to be adding more bookkeeping, you might want to think about increasing the ways the players can recover from exhaustion unless you all like the idea of waiting around for a few days to get enough long-rests to recover from a near-death encounter.
I’m curious about your campaign and group and would love to hear more.
We did some pathfinder 2e about a year ago but I couldn’t keep it up as I’m honestly quite tired of the genre (d20 heroic fantasy) but there are some neat additions to the genre the past couple years.
Sounds like an amazing campaign, thank you for sharing
The exhaustion / nimble dying rules sound like they would facilitate the “the Dieselpunk pulp fantasy vibes of Dishonored mixed with the socialist weird fiction vibes of Disco Elysium”
I totally get the charm of the roll for initiative and the randomness that d20 brings to the game both in the to hit and the initiative roll. If you are comfortable with the system that is just as valid as someone that changes systems frequently, having fun telling a story together is the most important thing to me.
Leaning into the exhaustion mechanic could be effective, spending more time investigation means you get more exhaustion. A fail forward consequence could be a level or two of exhaustion in addition to the usual HP loss / status effect / item loss.
Is there some sort of Dieselpunk way of removing exhaustion at the cost of HP?
How many of the players are full casters?
After having run many “tactical” systems I think it isn’t for me, I resonate with the approach you described and like the pie/meal analogy.
While you would need to tweak the setting a bit, The Between could be a great fit or Blades in the Dark. Especially BitD if you want to lean into the faction aspect, it is known for being a “heist” game but expanding on what the concept of a “heist” is can open it up to more robust campaigns.
Honestly though it sounds like you have a great idea for a game and using what works for you! Reminds me of some dimension 20 campaigns in the best way, and Eberron is such a cool setting