A fighter performing a Deed every turnI just read it. Flavor-wise I love it, but from a game design perspective there’s no cost. Maybe that’s the goal: to have warriors attempt a Deed every turn. But for 5e I would rather there be a cost.
Off the top of my head, something like roll with disadvantage, and if you are successful you can choose from various effects to impose on your target until the start of your next turn.
(a) Makes each turn have more narrative impact
(b) Brings fighter turn spotlight time up to approach spellcasters
The alternative to "you do a deed every turn" is "your baseline turn is 'I attack and roll damage'". If combat is extremely fast and longer turns are rare, you'll do this again in a few seconds, and that is ok.
But in a game where other character types are casting spells which are bundles of complex rules, it doesn't make sense for the narrative impact of the fighter's turn to be that short.
Now, if a fighter's damage is so high that most of the fighter's attacks drop foes, that is its own kind of narrative impact. Or if monsters reacted to damage in narratively interesting ways, but that is also atypical.
Instead, the impact on the narrative of a fighter's turn is often "ok, a counter to end of battle has been decremented after some die rolls".
Especially if you delay this to mainly being effective at later tiers, there is plenty of "balance room" for deeds that impact the narrative in 5e.