Hello everyone:
I am announcing that E&C will be the new Sub-AC for OGBM and related gargant-based lists.
He and I had some correspondence a couple months ago related to the supplement he is developing and had some excellent ideas that helped break me out of the mental rut I was in regarding the list.
I have marked up a 3.0 (because there are some relatively extensive changes) for him to work from, so it's up to him to work from there. To highlight the changes:
1) Grot Attack special rule is out.
2) Gargant discount is out. However, all Gargants come with a "free" Kustom Bitz swap. (With the standard Gargant options, this allows quite a bit of customization out of the gate.)
3) Support formations are 2/gargant.
4) Grotnoughts are out (I hate it, but they just don't seem to work).
5) Kustom and Krawla Gargants are out. Kustom aren't needed based on other flexibility changes, and Krawlas have a new manifestation.
6) Kustom Bitz upgrades have been completely redone.
6a) All Kustom Bitz now replace weapons. That allows the weapon swaps to be on par with other options, whereas they were very unattractive previously compared to the "add on" upgrades (and remember, the first swap is free). Non-weapon upgrades were modified for balance as needed.
6b) A lot of the weapons were cut, as they were of limited use and generally went against the abstraction principal of Ork lists.
6c) Several questionable upgrades were cut.
6d) A second tier of Big Kustom Bitz upgrades were added for +50 points. This covers the bigger upgrades, but also has an option to take a second Kustom Bitz as well. That gives another level of customization for greater specialization/optimization, but at a cost, much like the multi-weapon premium in the AMTL list.
6e) A transport option has been added as an upgrade. Basically, this allows you to turn any Gargant into a Krawla version. This comes with a +5cm speed upgrade, but it is the only possible way to upgrade the speed of a Gargant (max speed 20cm). It is a Big Kustom option (so it costs points) and requires the normal weapon swap. To give a reference point, a Gargant with the Krawla upgrade has the same speed and toughness as the old Krawla, with better firepower and FF, but costs more.
The transport option is a big change and may need adjustment. However, I think it nicely captures the Krawla idea and controls the speed issues in one stroke.
Also, I like it as a "generic" transport upgrade because it allows more modeling opportunities. It could be a Krawla, or it could be a normal gargant with extra boiler tanks and an assault ramp where the belly gun would normally be, or whatever (old skool, silly, oversized, "red wunz go fasta" feet...).
7) The bommers are out, replaced with the DC3 WE bommer, a la Forgeworld. This eliminates the token 1BP template issue and keeps the "like normal orks... but bigga" idea in the list.

I'm assuming E&C will want to have the Mega Gargant in the main list, at least for test purposes, much like the Imperator in AMTL.
===
And on that note, I'll let E&C take over.