capefeather
spork
srk1214
TheMantyke
I slated all of these submissions because I respect the competitive differences, but on the whole each of them has the true key moves needed to succeed. This makes me happy, so honestly any of these could win and CAP 2 would succeed. I ordered my votes even though it doesn't matter for the purpose of readers knowing how I feel.
That said, I appreciate a few things over other things competitively. I believe that Moonlight is a better choice than Pain Split, that Horn Leech is a very necessary part of the movepool, and that Night Shade is an option I desperately want CAP 2 to have in its arsenal. I also believe that from a flavor perspective, we can forge new ground in CAP by having an in-game event for Sketch. Thus, you'll see that I support those more rigorously than the egg group solution.
capefeather has masterfully crafted a movepool that fits all of these requirements. While capefeather's movepool lacks in many of the 'cool' moves like Gravity and even Ingrain, it gets everything else right, and so is my top vote. It is also the only movepool of the 'in-game event' list that has both Giga Drain and Horn Leech, which matters a lot to me for bulkier sets. It is also the smallest physical movepool of the list, which pleases me a lot because CAP 2 doesn't need a big movepool and this fits my ideals well. spork's lacks Giga Drain and Night Shade, but has Horn Leech and some neat options like Reflect and Gravity, so it is my second choice. srk1214 and TheMantyke both lack Horn Leech, which puts them below the other two, but have Giga Drain and an assortment of other moves. srk's has Night Shade, putting it above TheMantyke.
I appreciate the work put into the other movepools, too, though. I think juicy has the strongest Pain Split movepool, as it has both Horn Leech and Giga Drain, offers interesting choices in Ingrain and Taunt and Gravity, and it packs Night Shade for added excellence.
Good luck to all entrants!