OK.

It's not a big deal really. A Hi/lo hub can be a tad lighter, but symmetric hubs are faster to build. 'Course, there's a balance point somewhere, where the assymmetry is big enough to shave a few grams, yet small enough not to require severe bending of the spokes.
Strength/durability-wise, I'd guess we're talking about single digit percentages in improvement.

If you want a spoke that's 2.3 mm at the thinnest, it'd have to be thicker at the ends. Normally hubs aren't drilled to accept anything thicker than a 2.3 mm spoke. I think you're out of luck there.

We'd better define strength.
If you want strength as in resisting collapse, big amounts of cross section is your friend. The more cross section, the more laterally stiff the wheel becomes. The stiffer it is, the more it'll take before collapsing into a taco. (and sure, the rim plays a part in this too.)

Next thing is durability. A common spoke killer is metal fatigue, which comes from a spoke seeing big changes in its tension.
Horribly simplified, in the finished wheel, swaged spokes AKA thinner spokes will have stretched more(and is ready to spring back more) than a thicker spoke(less stretch, less springback), so as the rim compresses they're more likely to remain tensioned - which protects against fatigue.

If durability is your thing, then you want thin spokes, many of them, in a really rigid rim.

IME, there isn't that much of a point to build for extreme durability. (again, better-than-needed isn't a tangible benefit)
There's usually something else that ends up retiring a wheel before that stage is reached.
What good is an expected life of twice-around-the-world if you hit a bad pothole while riding coast-to-coast? Or theft, or vandalism, or....

There are spokes with a 2.3 mm elbow, and an 1.8 mm shank. The value of this is somewhat debated.
On the good side, it can provide good support and a tight fit at the hub.
On the bad side, bending a 2.3 mm spoke at a right angle means that the material at the outside face of the bend has to stretch more(and the inside has to compress more) than for a 2.0 mm spoke - which some claim creates fracture points on pretty much the molecular/crystalline level of the metal.