The Wheel would have to know and recognize a specific individual and then will them to have a set of abilities. That to me implies sentience.

Playing the numbers by arranging for the right set of genetics seems far more likely to me. It would be like a trigger, once Rand's genetic code appeared, the Wheel was able to place the soul of the Dragon in that body. nothing says they have to be genetically identical, merely hold a certain set of genetic markers in common for the body to be capable of displaying the abilities of the Dragon. Who knows there could be millions of people in the world that have the necessary traits to become the Dragon.

The Wheel clearly made arrangements for the right parents to come together for Rand to be born, giving Gitara the Foretelling that Tigrane had to leave Andor and seek out the Maidens, ensuring the timing for Tirgrane to give birth on the slopes of Dragonmount, making sure Tam found Rand and could take him to be raised by the old blood, but be of the ancient blood etc... if there was no worry about genetics (and I'm simply speculating) why would the Pattern go through such lengths to ensure the very specific parents for Rand? Why not simply have a random Maiden become the mother? Why not imbue Galad with the abilities of the Dragon if the father wasn't important?

Seems to me The Wheel arranged for probabilities to create the correct body for the soul it had in the wings.

As for circles, I see what you are saying, and it could very well be the way, but we've not seen any instance of two Channelers working on a weave together. And what happens in a circles where only a man can lead or only a woman can lead? Why wouldn't the skilled individual leading simply grab a handy angreal or sa'angreal to do the task?

It makes no sense that Siuan led the circle to Heal Mat when she is at best an average Healer, why did she at no point shift control to someone more skilled in the area? When the FS plot to gang up on Rand early in the series was afoot there was open discussion of only one individual controlling the link, why not pass control around to most effectively fight Rand with each individual's strengths being put into play? Certainly distrust played some role in that, but why not even discuss strategic opportunities?

I think we view what "abilities" are slightly different. I see this as special by-products of strengths, i.e. Egwene can sense ore in the ground, or Aviendha's reading of ter'angreal or Nynaeve's Listening to the Wind etc... none of these things would be passed along with a Link, but I don't see flow affinity as the same thing. Egwene is strong in Earth (and as such she has special abilities from this strength), she would naturally contribute that strength to any circle she participated in...

I see every Channeler's strength as something akin to a weighted average. If Egwene is a 18 in Earth and a 16 in air there is no reason to believe that she is only passing along 14 Earth to a circle...

Let's quantify what I mean further (all numbers are made up):

Egwene, Aviendha and Elayne Link

Egwene = 18 Earth, 18 Spirit, 16 Air, 15 Water, 13 Fire

Elane = 18 Fire, 18 Air, 16 Water, 16 Earth, 12 Spirit

Aviendha = 18 Water, 18 Air, 15 Spirit, 15 Fire, 14 Earth

In a link they = 48 Earth, 45 Spirit, 52 Air, 49 Water, 46 Fire ...

Swap Metaara for Egwene

Metaara is 18 Water, 18 Air, 16 Spirit, 15 Earth, 13 Fire

in this link they would be 45 Earth, 43 Spirit, 54 Air, 52 Water, 46 Fire

Furthermore what if you replace Egwene with someone like Moiraine?

Moiraine = 12 Air, 11 Water, 9 Spirit, 7 Fire, 6 Earth

Now you have a link that is

33 Earth, 36 Spirit, 48 Air, 45 Water, 40 Fire

Each contributes her proportionate strength in each flow to the circle. When Egwene is leading she can make Cuendillar and sense ores etc ... but Elayne would not be able to do these things as they are special abilities specific to Egwene.

Every individual has a specific set of strengths that they have no real control over, it seems highly unlikely that Egwene would only contribute only 14 Earth to a link because the Leader can only contribute 14 Earth at least not without the circle losing overall strength ... of course in this scenario it's also likely that Egwene would lead the link if they were going to make Cuendillar