Agreed on both counts! She was trying to establish another link, based on formality and tradition, to a throne that was only going to be taken by violence. She might have been a good logistician and maybe even a decent plotter but she was way behind the times.
Bingo. Give the man a cigar.
Making matters worse, Margaret and her advisors are echoing Arbellatra's
actions without understanding Abellatra's
thinking.
Even before we got the behind the scenes story in
AotI, I can't imagine anyone with an IQ over room temperature in Celsius believing the story that Arbellatra was going to end the Civil War, act as Regent, and then meekly hand over the Iridium Throne to whatever descendant of Cleon that Moot might be able to dredge up. Arbellatra knew from the beginning that, absent slipping on the soap first, she'd eventually shift from Regent to Empress. She knew the Zhunastu bloodline no longer mattered so the entire Regent angle was a just a way to get everyone who mattered comfortable with the idea of Arbellatra running things.
Margaret, on the other hand, thinks bloodlines still matter and that acting as the guardian of the Alkhalikoi bloodline will put her on the Throne. She's aping the words and actions without comprehending the thinking behind them.
PS-Why did the Vermene turn on her?
Meta-game answer? The Endless Rebellion.
For whatever reason, they wanted the Rebellion to run on like the Energizer Bunny. Everything plausible, implausible, and outright suspender snapping flows from that decision. Too many factions lasting too long? Endless Rebellion. Vargr and Aslan invasions despite being impossible by
MT's own setting materials? Endless Rebellion. The Solomani bogging down? No alliances between moderate factions? Antares flip flopping and staying unified? Every decision and event being the worst possible one? Anything which makes no freakin' sense whatsoever?
Endless Rebellion.
In-game excuse? Tukera and every megacorp but the Vilani ones fractured just like the Imperium did. Tukera fell apart and the bulk of Vermene's assets sided with a faction which opposed to the faction which supported Margaret.