*also the direct Uriel=Before power comparison is perhaps a key towards walkers and angels in fact being on similar plains of existence.
I pretty much figured the angels and the Outsiders must have been at odds in prehistory already. Uriel said in SG when Charity wanted him to avoid risking himself against the squires while he was mortal that he'd been fighting in wars before Earth existed. The Fallen rebellion is probably one, but for it to be wars plural, the outsiders look like the next most likely candidate. Particularly given Before's claim that this was once their world.
That said, his specific answer was that Walkers are on a level similar to archangels, not absolute equality. Like maybe a Walker could make Uriel sweat in a straight fight, but he'd still have a healthy advantage.
Also, the answer to the question about what Lasciel would have done for Denarian Harry kind of makes me want to revise the probability of Mirror Harry having taken up the coin. I had thought Hannah Ascher was basically already constructed as a foil to Harry who said yes to Lasciel, and it would be repetitive to make that one of the differences in MM. But James Bond Harry might be different enough to make for a good antagonist.