It's always been obvious that racials need some balancing. While some races are popular anyway because their lore appeals to some players, that isn't a sufficient reason to leave them underpowered(I'm looking at you Bosmer).

Let me start with categorizing the passives and proposing a template that race should follow. I believe every race should have one of each to be balanced.

Maximum (A)ttribute bonus: Those are the 6% for both max stats, or the 10% for one. They are extremely powerful, being multipliers, making them scale with enchantements, set bonuses and the like in endgame. Note that they give either 10% or 12% total. I suggest they all get scaled up to 12%.

(S)mall, sometimes gimmicky and situational bonus: can include a 3% to a max attribute to compensate for all the situations in which it is useless.

(U)Unique bonus: sometimes an exclusive yet simple bonus(like Carnage), sometimes a good proc passive(Red diamond). It's what sets most of the flavor of the race.

Let's start by listing the races that follow this template and are mostly fine:

Bretons are in a good spot. They have magicka as their (A), Spell resistance as their (S) and Cost reduction as their (U).

Redguards will be good too, once stamina builds are made competitive. Considering stamina recovery as their (S), they end up in a decent position. Adrenaline Rush(U) is especially potent.

High Elves are right where they belong. Magicka recovery as their (S) and bonus elemental damage as their (U)

Dark Elves are similar. They end up with a lot of attribute bonuses and a (U) that, while only affecting fire, is quite potent.

Now let's speak about underpowered races:

Orcs have an (A), robust which is utterly terrible(see below) and Swift, which, while unique, is extremely gimmicky and obsoleted by things like Bolt Escape. It could count as their (S), but I suggest adding a 3% max health to it. Another option would be 3% max stamina for more coherence with the name, and to change their (A) to pure health. Giving them a proc based (U) that somewhat imitates the "berserking" they have in previous TES games could be interesting.

Bosmers have stamina recovery(S), Resistance which is another (S), and Stealthy, which I believe should also count as an (S). Stealthy is the problem here: they share it with Khajiits, making it invalid as a (U). Adding the 3% max stamina to it and removing the resistance entirely could work. Replacing the recovery with a pure Stamina bonus would give them the highest Max stamina in the game, essentially giving them the potential for the hardest hits with stamina weapons, including bows, fitting their lore. Their (U), on flavor, could be something that has to do with their carnivorous nature; among other possibilities.

Khajiit have a functional (U) in carnage and Stealthy as a (S). Their only problem is Robust being terrible, it should be replaced with an (A).

Nords have a Resistance (S), an Armor bonus (S) and Robust. replacing their armor with some kind of proc based war cry (U) that buffs their armor in a way, among other things, would be a nice way to keep that while bringing back war cry. They then need an (A), which could be pure health, to replace Robust.

The last underpowered race, and quite a special case, is Argonians. They have a ton of gimmick and situational bonuses, but even should they meet a situation that exploits all their strengths, they wouldn't be the best. I suggest tying the potion effectiveness bonus and the +% healing recieved into the same bonus, as their (U), keeping the resistance and giving them an (A). In lore, Argonians have been somewhat hard to figure out, and/or inconsistent. They have been said to be decent mages, known guerilla fighters, and to be resilient. Should all (A)s be buffed to 12% total, they could have one that gives them 4% to all max attributes.

That leaves us with the last race, the most powerful. Imperials have two (A)s. While their (U) is fine, removing one (A) would be a good start. You could give them Rugged as their (S) to keep them a relevant race for tanking, perhaps under another name.

That leaves us with one thing to talk about:

Why is Robust terrible? Health recovery is a low effect, barely relevant attribute. It's only in effect when you're not topped up(not often unless soloing in PvE, which is irrelevant to character optimization), and even then, whatever you gained from it is irrelevant simply because you'll naturally be overhealed for more than this recovery gave you in the first place. The value on the Robust passive itself is extremely low, too. It is by a large margin the worst passive in the game.

Note that while you might disagree with individual suggestions, the main point of this thread is to get that template to all races. Flavor in game design can only bring us so far before causing significant balance problems, and having such a basis would make it easier in the future to balance things out.