Unless something's been added since I last decided to release the Shambler, I don't see any point in fighting it. You get a few mods and lose all your consumables in the process.
Standard Fireangel was my preferred build way back when before the requirements were made more "practical". I think they were... Badass, Juggler, lvl1 Ironman? Something like that. Worked well for me as I'll pretty much always go for Badass and Juggler unless I'm on a challenge game, and it didn't restrict your weapon use all that much.
I'll also argue that Shottyman is nigh-useless: You shouldn't ever be reloading in combat. If you're fighting when positioned somewhere you can't retreat from, then you have bigger problems than reload times. Unlike 10mm, shotgun ammo can be found in large quantites right through hell, so there's nothing stopping you from just scouting constantly and leading investigating enemies to corners from where you can knockback-reload-loop them, or (in worse scenarios) just spamming that out-of-sight Baron/Mancubus with 1-damage shells until it dies from attrition.
The Cyberdemon's rocket launcher is probably the only one that suffers from that obnoxious Fireangel bug :/
I think Cybie's rocket launcher is less a rocket launcher and more a BFG. If that's the case it wouldn't have a "projectile" to cause a direct hit, hence the bug.
On the subject, I'm liking his new(ish?) AI. No more pillardance cheese!