This, honestly.
If it were Alleria or Vereesa that are reminded of Lirath when interacting with Anduin, I think that’d be fine. It’d certainly help explain why Alleria would feel any kind of loyalty towards Anduin outside of her loyalty to the Alliance. Its a little difficult to image a lot of characters letting Anduin take the lead, but when you have Alleria who’s been fighting since the Troll Wars, as well as Turalyon who has over a thousand years of combat experience, one has to wonder why they’d follow Anduin.
For Turalyon its easy enough to just assume he’s just following human culture, but Alleria? The idea of her seeing a bit of Lirath in Anduin would work. She’s a character strongly defined by her love, after all.
It’d even go some lengths to provide another perspective as to why Vereesa and the Silver Covenant have continued to support the Alliance’s efforts. There are reasons already existing, sure, but this would just add another way to look at it.
Sylvanas though? It just doesn’t quite feel the same. Honestly, she should see more parallels between Anduin and Arthas, and if that HAS to have a good connotation to it, she could ponder if Arthas might have turned out like Anduin had he not run afoul of the Scourge/Legion. If that had been a catalyst for her to do some soul-searching on her own actions in undeath, and led to personal, internal growth, that’d be fine.
Just my two coppers.