Hi everyone,
I am a fan of LiftingNerd's Carpet Bomber and did worry about the expansion. I'm glad to report that the build is alive and well. I cleared the final boss in Act 4 over the weekend. I haven't tried the new Atziri, but did clear her pre-wipe and think it's doable given what my kinmates reported (I didn't have any Midnight fragments for testing).
Here are some modifications and observations.
1. In general, we kill enemies faster! Despite the changes to Greater Multiple Projectiles, Fireball itself is stronger. There are also some juicy fire passives and jewels. For boss fights, add some Fire Traps and Searing Totems (see below). I have yet to test Magma Orb and Flame Totem, but there are lots of options for more dps.
2. The Explosive Impact passive node is terrific because it adds both fire damage and area of effect radius.
2. The greater dps also means that we can drop the Flammability curse in exchange for more defensive curses. I generally use Enfeeble, but Temporal Chains is great too (and it adds more time for burning!).
3. I stopped using Arctic Armor. It's probably still viable, but I didn't bother testing it. For defense, I used the Chaos Golem and the Lightning Coil chest. I also stopped using Spell Totem + Skeletons in favor of Searing Totem for a bit more DPS. The skeletons are great if you need a bit more defense 'though. I realize that not everyone has a Coil, but I don't think its that necessary.
4. The new skill, Flame Dash, can replace Lightning Warp. Flame Dash works great even without support skills and is a perfect compliment to our build.
5. I dropped Eldritch Battery since I didn't need it for Arctic Armor. Instead, I took Constitution (southwest part of the tree) and a few other life nodes. I'm still working on my passives, but it's been fine. Also, dropping Eldritch Battery means that we have Energy Shield again, so you can go heavy on ES as another option.
6. I haven't found a great replacement for the cast-on-damage-taken. For now, I have a temporary level CWDT setup (cwdt + immortal call + increased duration) and self-casting Enduring Cry.
This isn't meant to be a new build guide, and I'm still far from rebuilding my character. But I did want to say that our beloved Carpet Bomber is still working. Thanks LiftingNerdBro! You created a solid and fun build that remains viable. I'm sure you'll have more sage and comprehensive advice than I provided here.