I can't make a comment on the Castle maps since I haven't played them. I'm not sure why you still write that Ragnarok is large enough for 16 players. With sprint/mobility/DMR, it hits max players at 12, although 10 has been fairly back and forth for quick combat. Exile, Vortex, and Longbow are Dominion based, but I only look at Longbow positively, and not the other two (16 is too many for Exile, Vortex has no flow or identity, it's a mess). Wreckage is like Vortex, just smaller. Settler is also not large. It's getting jammed down your throat if you attempt to play the CTF playlist. Sometimes two since there's also Infinity CTF.
These maps as a whole don't really spark much intrigue for their Halo 5 suite.