PvPers care about performance. Organised, competitive trial players care about performance. It matters to them, but these groups typically overstate how relevant racial passives are to everyone else. Their assumption is that everyone eventually progresses to the highest level of endgame, but I think most people don't and it's fair to say that, up until that point, racial passives matter diddly squat. At the very highest level you may see performance differences around the 3% ballpark in terms of DPS. This only matters for pushing scores and setting world records. What makes or breaks your performance much more than that is your proficiency with your skill rotation. For example, I have played this game for 6 1/2 years, albeit mostly as a PvPer. My proficiency in PvE, against a target dummy, is about 66% that of the best players. In other words they do 50% more damage than me, because they're better at PvE than I am with the same build. On the other hand I will probably beat the crap out of 95% of players in PvP and PvE alike. In this context, do you think 3% matters? I know it doesn't. Let me run through the races for you, though. The TL;DR is: Don't choose Breton. That's about it.
Altmer: Two out of 3 passives, Spell Recharge (sustain) and Elemental Talent (damage), now also apply to stamina builds. Traditionally a magicka race, this now gets my vote as a possible option.
Wood Elf: Totally fine. Stamina race majoring on speed and sustain. Nice.
Khajiit: A universal race. Building for crit is meta for PvE. Khajiit does extra crit damage. Recent changes to crit have probably nerfed this race a bit, but still good.
Nord: A tankier race that doesn't make for the best damage dealer, but the unique ulti-gen passive synergizes with DK. Nice.
Dunmer: The traditional pick if you're unsure whether you want to play mag or stam. Both stats and damage. Nice.
Argonian: A universal race, maybe more for a tank or healer. Can't say no to extra healing and sustain in solo play. Nice.
Imperial: Another universal stamina or tank race. Nothing wrong with this either. Universal cost reduction including, I presume, base skills (dodge rolls, blocking) and ultimates is nice.
Breton: A pure magicka race. The one race that brings nothing to the table for stam DK and that I would not choose.
Orc: Speed, damage, self healing, some stamina. Nice.
Redguard: It's a stamina race, but I think the weapon cost reduction makes it uniquely suited to specific builds. Probably better for stamsorc builds than DKs as a whole. Good in the past, but regarded as generally weak these days. Then again: Talking about the highest levels here. Still a stamina race and, thus, suited to stam DK.
PvPers care about performance. Organised, competitive trial players care about performance. It matters to them, but these groups typically overstate how relevant racial passives are to everyone else. Their assumption is that everyone eventually progresses to the highest level of endgame, but I think most people don't and it's fair to say that, up until that point, racial passives matter diddly squat. At the very highest level you may see performance differences around the 3% ballpark in terms of DPS. This only matters for pushing scores and setting world records. What makes or breaks your performance much more than that is your proficiency with your skill rotation. For example, I have played this game for 6 1/2 years, albeit mostly as a PvPer. My proficiency in PvE, against a target dummy, is about 66% that of the best players. In other words they do 50% more damage than me, because they're better at PvE than I am with the same build. On the other hand I will probably beat the crap out of 95% of players in PvP and PvE alike. In this context, do you think 3% matters? I know it doesn't. Let me run through the races for you, though. The TL;DR is: Don't choose Breton. That's about it.
Altmer: Two out of 3 passives, Spell Recharge (sustain) and Elemental Talent (damage), now also apply to stamina builds. Traditionally a magicka race, this now gets my vote as a possible option.
Wood Elf: Totally fine. Stamina race majoring on speed and sustain. Nice.
Khajiit: A universal race. Building for crit is meta for PvE. Khajiit does extra crit damage. Recent changes to crit have probably nerfed this race a bit, but still good.
Nord: A tankier race that doesn't make for the best damage dealer, but the unique ulti-gen passive synergizes with DK. Nice.
Dunmer: The traditional pick if you're unsure whether you want to play mag or stam. Both stats and damage. Nice.
Argonian: A universal race, maybe more for a tank or healer. Can't say no to extra healing and sustain in solo play. Nice.
Imperial: Another universal stamina or tank race. Nothing wrong with this either. Universal cost reduction including, I presume, base skills (dodge rolls, blocking) and ultimates is nice.
Breton: A pure magicka race. The one race that brings nothing to the table for stam DK and that I would not choose.
Orc: Speed, damage, self healing, some stamina. Nice.
Redguard: It's a stamina race, but I think the weapon cost reduction makes it uniquely suited to specific builds. Probably better for stamsorc builds than DKs as a whole. Good in the past, but regarded as generally weak these days. Then again: Talking about the highest levels here. Still a stamina race and, thus, suited to stam DK.