That’s what Jaina is for, she’s the heir to that throne, and Jaina is all Stormwind needs to help strengthen the Alliance between the two nations…
So Tess makes the best candidate, as the Gilneans still live and their former capital still has the possibility of being resurrected, especially with the forsaken/horde having been driven out of the nearby Undercity. So uniting those two kingdoms with a marriage would make the best choice.
Jaina was an adult when Anduin was still a kid… She’s approximately in her 40s. Doesn’t make sense for Anduin to seek out a cougar, and as stated above, it doesn’t serve any benefit to Stormwind or anyone, for her and Anduin to hook up.
Draenei, I doubt, no evidence in lore or game that even offspring is possible between those two species, unlike elves and humans where hybrids do exist, also have to keep in mind that the hybrid children between elves and humans are sort of outcasts as humans in the warcraft universe are quite prejudice and elves are quite high-standard/snobby and look down on lesser elves… So yeah I can’t imagine a Human-Draenei hybrid would go down well, and their offspring be accepted by the people of Stormwind as royalty.
Furthermore, Anduin knows better than to marry a Dwarf, he’s had plenty of troubles with Moira and the other Dwarves to know they are quite a handful, have a lot of issues, and easily have trust issues and turmoil amongst themselves… also Anduin can’t be with a Dwarf due to the fact that they have a thinly stable system ruled by the 3 dwarven clans… so if he decided to marry a Bronzebeard for example, the Wildhammer and Dark Irons would probably riot, and it would destroy the balance… and vice versa if he married into one of the other clans… plus same as the Draenei… I can’t imagine the offspring between the two would go down well with the people of both nations.
Mostly agreed with one quibble: a marriage between Anduin and Tess doesn’t unite the kingdoms, it unites the crowns in personal union. Their son will be King of Stormwind and King of Gilneas, not King of a combined kingdom. It’s like England and Scotland prior to the Acts of Union in 1800.
Also gotta remember, that there’s only two human kingdoms remaining in all of Azeroth… Lordaeron is no more, Theramore is no more, etc… and all the little various factions of humans that aren’t apart of Stormwind, or whatever have all been crushed and weeded out by us over the decades… Leaving literally just citizens/subjects of Stormwind and Gilneas in all of Azeroth… So in otherwords, Anduin’s and Tess’ son would literally be the King of the entire Human race (with exception of Kil’tiras, but Kul’tirans are essentially a different species; so they don’t count ;P)
In 9.0 we discover a new continent on the other side of the world. To avoid a war with a 3rd faction, Anduin decides to wed a daughter of the most powerful clan on the new continent.
The expansion consists of farming cloth for wedding clothes, herbs and meat for the feast, ore for the new rings and crowns, inscribing wedding invitations, and making a viable seating arrangement for the warring clans at the wedding.
The raid bosses will be different living flowers for the legendary bouquet.
Kul’tiran a different species/breed of humans yes, that’s like the difference between the Vrykul and humans, drastic physical differences.
Gilneans are still human… even the Worgen as they aren’t a different race. Worgen are literally just humans afflicted with a curse. Plus not all Gilneas are afflicted with the worgen curse… plenty of non-worgen afflicted Gilneans, such as Tess Greymane.
Wouldn’t that be a good thing though? It would sure make for an interesting story.
The King remaining in Stormwind and handling all the politics, and the Queen out and about, assisting in saving the world, once in a while returning to visit.
And if she died? Well… That would make for an interesting story for Anduin. Especially if someone in the Horde killed her/caused her death.