Yeah the problem is that Indomitable was kind of... situational before.
If you flubbed a good Fighter save like STR then sure, you could roll it again and probably succede. But if you're targeted at a save you're already bad at, then rolling again probably won't help you that much. Especially...
I do find it a bit odd that dragons being color coded is considered cheesy considering it happens along familial lines. I wouldn't expect a pair of Clydesdale horses to produce a little pony.
Honestly my favorite 'PC Wizard' statblock is the Legendary Archmage from Monster Manual Expanded 3. I think it's a good compromise between usability (It has a post-MPMM style spell list) and not having completely arbitrary At-Will powers.
Honestly even if torches are seldom used I've never had trouble making darkness matter in my 5E Game... unless there was a Twilight Cleric in the party.
Yeah I would probably just adopt a version of my Spelljammer ship rules. Slow the turns down so that they take place over several minutes to account for how slow aquatic ships are by comparison.
But why tho?
This is where you're losing me. Mechanical consistency is useful, but not at the expense of playability. Representing an NPC the same way as you would a PC of the same level leads to multi-page statistics full of mostly-useless information that isn't going to even be relevant when...
I don't even know how to respond to this. We have rules so that the game is 'fair' (for whatever difficulty the players and DM agree to) and it's not just a playground game of 'nuh-uh, my monster is totally immune to your spell!'
You think the rules should reflect the fiction? Sure, I agree to...