I couldn't agree with this more. Metallurgy is cute, but for most packs it's a prime example of "what to cut away first."
The rest you mentioned are all purely opinion pieces. You're unfortunately inviting a large storm of discussion on the merits of IC2 and BuildCraft (very polarizing subjects).
Personally I'd keep everything else you mentioned, pare them down brutally with MineTweaker, and have fun.
But seriously, my opinion is irrelevant: all you're going to get is opinions on what makes every individual's game more fun for that person
edit: Woops
, I see you explicitly acknowledged "opinions". So, much of my point above is silly. But perhaps consider making a thread for a topic that invites some fun (and heated) discussion