This is so confusing.

From my understanding, whenever you do an attack roll, you add the result of the roll to a value called "Affinity". Whenever you make an attack roll and have reached 100 affinity, you can use all your affinity to get a crit.

What does the initiative order have to do with any of this? I'm not supposed to add the number rolled on to "affinity" am I?

If I understand this correctly, picking up this feat means keeping track of another value, which might slow down play.

This feat is very strong if you make multiple attacks per turn, but in that case, it slows down the game more. Don't like that

“While in initiative order” was to prevent players from swinging at trees to rack up affinity out of combat. It was meant to be a “battle momentum” mechanic, embodying the fantasy of a combatant who gets swept up in the rhythm of battle, growing deadlier as the fights wear on. That’s why it resets on rests.

In practical use, we haven’t found it to be difficult to track since we’re all using D&D Beyond to roll dice in the shared log. I’ve discovered that my players are enthusiastic about tracking a number that allows them to critically hit enemies automatically, and the log helps keep them honest. I can see issues with players fudging numbers to get auto-crits more often, but then the issue is a player fudging numbers to begin with.

As far as slowing gameplay is concerned, we haven’t seen any issues there either. We’ve found that a spellcaster looking through their spellbook in the middle of combat slows the game more than a fighter taking four attacks on their turn and writing down four numbers.

However, I acknowledge that your mileage may vary. If you feel that it would impede quick combat, I encourage you to exclude this feat from your campaign in favor of simpler options.

If you have any constructive criticism, vis-à-vis supplying a possible solution to the problems you feel arise with this feat, feel free to add it.