In a weird and atypical fashion, it was WK that was the more complete show in terms of story and feeling substantial and not just a collection of good matches like WM was. WM was a great show, but a great show that exists with the WWE storylines being a complete fukking mess and a show that left damn near the entire roster with NO momentum coming out of it. Aside from Seth and Randy, everyone comes out of the other side of WM fukked up.
Reigns' situation is bleak, Rusev has nothing, instead of elevating talents to make the midcard titles worthwhile they instead just put them on two of the most popular wrestlers in the world because they had no room for them, Bray has nothing, Brock, nothing. Trips/Sting was a great spectacle, but there's absolutely nothing to come from that and until they manufacture another storyline for Sting down the road there's no reason to even think about him until then,
These big shows are supposed to cap off the "year" and kick off the new one, and have you excited for what's to come. Two weeks later and there's nothing to be excited about coming out of WM. Even the Post-Raw Mania which is usually an easy classic episode was bad.
WrestleKingdom had more going for it with the MiSu/Sakuraba, Suzuki-gun/NOAH, Nakamura/Ibushi, and the biggest chapter in the Okada/Tanahashi saga yet. It just accomplised more as a show.