The pattern picked someone who didn't believe in the absolute authority of the white tower, while at the same time strong enough to provide solid leadership after the turmoil of the last battle.

That the pattern was able to sacrifice Egwene for the greater good of the world was just a good bonus.

Killing Egwene was sad to me, and something of a waste. Much like damane remaining enslaved and the BT being without direction/stable leaders

I know. I just pointed out Brandon's answer on the Oaths isn't as definitive and conclusive some made it out to be. It's far more likely there was nothing about the future of the Oaths in RJ's notes (and in the past Brandon's "I'm not sure/not that I know" often got contradicted later by Maria, incidentally). In another answer Brandon suggested it's up in the air how long Cadsuane would live. RJ would probably have given us many more little clues later, writing the outriggers, so it's probable a few things in the resolution of the series he turned into hooks. It's unlikely his "two sentences" synopsis for the outriggers includes developments at the WT. Not only his timeline of 5 to 10 years after TG left time for things to develop, but outlining and writing those books also left him a lot of time to figure out himself how he wanted some of the loose ends like this to have developed during that timeline. Bottomline: Brandon doesn't seem to know much more about the future of the world that's not in the books.