What do you think will happen to the Tyrells long-term? I've heard theories Margaery might end up being killed by Robert Strong.
Call me a silly optimist, but I think things are rosy for Willas and Garlan. The two together actually are a pretty ferocious combination. Willas is thoughtful, intelligent, and above all, perceptive. Mace is not quite the dunce he makes himself out to be, but Willas has a better knack for the long-term than the Fat Flower. Garlan is a tremendously talented warrior, but is much more humble and patient than his brother. And from what I see, there is no sibling rivalry like you see in other families. Both Tyrell brothers know their strengths and, I don’t know about this but I feel confident in saying so, acknowledge the strengths of the other. I think Willas will be perfectly situated to handle the quickly crumbling political problem in the capital, while Garlan handles the military matters with the ironborn.
I’m less optimistic for Maid Margaery, because she’s in the middle of the hornet’s nest. The Mercy sample chapter let us see that Cersei is likely to beat her problems, and she might look to send Robert Strong to kill Margaery in a deperate attempt to short-circuit the valonqar prophecy, for her own sake as well as Tommen’s and Myrcella’s. Right now, she’s in Randyll Tarly’s custody, which if Tarly turns cloak for Aegon, might not bode well for her. She might be a hostage for Aegon the same way Sansa was a Lannister hostage (though I believe she’d be treated far better in any case and might even try to marry Aegon). After that, though the second Dance of the Dragons and the Great King’s Landing Kaboom might be a danger for her. She’s been able to handle everything the narrative throws at her so far, but that’s a lot of danger. I wouldn’t be surprised if she’s another victim of this mad game of thrones, one of many who perish in the final gasp of Aerys II. She might wheedle her way out beforehand and come back to Highgarden, to help Willas and Garlan manage the ship of state. If she does, watch out for those three. Those three together are powerful.
The one I think is doomed is Mace Tyrell. He’s overplayed himself. Sure, he propped up the sinking Lannister ship, but even the vast reserves of the Reach can’t save the kingdom by themselves. The friends in the Reach will betray him, and Mace will likely die as part of Aegon’s ascension, when the Tarly forces turn cloak and permit his host to enter the capital. This is actually a good jumping off point though, for Mace. It will allow his two sons, who are perfect for their tasks despite being the less-favored. For all Mace imagines himself to be a cunning politician and a dynamite wargod, those two actually might be able to back up those boasts with real substance.