hey yall need some game balance input that's beyond the scope of my usual megathread ramblings but also i don't want to wade into reddit. i'm running a campaign that probably would have been better in another system, but it appears i'm locked into d&d 5.5 and i want to mod the things i find most frustrating/unfun about the system out. i mostly stole/adapted ideas from Nimble and Draw Steel, just want to make sure they won't break anything & also have some other clarification questions for those who are familiar.
Nimble 5e Dying Rules
Want to use the Dying Rules from the original Nimble 5e hack instead of the default "unconscious + death saves" system. Pasted below:

The one difference is I want to try to keep Exhaustion as a debuff as well, since it's a lot more reasonable in 5.5e than it was in 5e. Here's how it works in 5.5:

Would that be too punishing? I'm open to straight up changing the Exhaustion system to a Wound system as the original hack intended, but feel like an interesting layer of challenge could come from having to manage the Exhaustion debuff. My games won't be too conservative about clearing Exhaustion levels. I use a modified rest system where a Long Rest is two days focused rest in a safe place (clears all exhaustion levels, mostly intended to be done between adventures/missions/story arcs), a Short Rest is a night of sleep (clears one exhaustion level), and the original version of short rests exist as a sort of mini-rest where you can use hit dice to heal and maybe roll a D20 to see if you can clear an Exhaustion level.
Also, if there's anything I should more generally be aware of about how this rule alters game balance do please sound off!
Ping-Pong Initiative
I basically made a tweaked version of Draw Steel's alternating side initiative since I find ranked init clunky & uninteractive. it goes like:
-Players roll initiative. The player with the highest roll goes first.
-DM rolls against the highest player-side roll, adding the highest enemy combatant initiative bonus to the roll. Higher of the two goes first (tie favors players).
-Combat then proceeds with both sides alternating taking turns until all combatants on one side have gone. Then, any remaining combatants take their turn in an order of their choosing, then the round resets.
-At the end of a player's turn, they choose the next player to take a player-side turn from players who have not yet taken their turn this round. The last player to take their turn chooses any player other than themselves to be the first player-side turn next round. DM chooses order of enemy combatants.
This one I'm most confident won't break anything, and am also fairly confident will be more fun than default initiative. I also had to change how surprise/ambushes work to accommodate it. Still, open to feedback.
Nimble 5e Mana rules - iffiest on these, but like a lot of aspects
Pasting below:

I enjoy the increased flexibility, but am I wrong that the mana-math just straight up gives casters more casts per adventure-rest-recharge cycle? I'm a bit wary of this since I think magic already kinda does too much, and the attrition game can be difficult enough to balance/prep for properly. Also, doesn't this break the intended design of Warlocks? It feels like they should use the half or quarter caster rules for the amount of mana they get (considering they get it back on a short rest).
I'm open to running this alternate rule but tweaking the math down a bit, but also want to make sure that won't break the intended design.
Anyway thanks for any help yall can provide nerds! keep on g@min g@merz 