The movement speed alone makes up for those lost shields... So does being able to take extra consumables (though I just used stronghold) and still have a free GS.
Not taking Hunter Mode does not in any way make a solo easier lol
I guess loufi has already addressed this, but the reason people skipped HM was to get full shields... a build that is only halfway decent because of GS. I don't remember what the "ez mode" solo vid had for a build, but there were definitely people talking about no-HM w/ GS as a miracle platinum build.
Armored compartments though.
Most of the time people who are looking for the "easiest" build and setup for a platinum solo will not be taking AC. I would agree that I would personally rather take it than GS.
You mean something like that : http://kalence.drupa...24N52334!DA.EG 
3150 shields + 40% DR + a dodge + a crazy dps with Flamer is what makes me put the GT among the easiest character to solo with. However, Flamer has a 15m range at best, so some setups wouldn't be so easy with him.
GS equipped on a Geth should cause the character to self destruct immediately on Wave 1 load.
But in any case, whether it is easy or not isn't the same as best, and I guess that is where I am getting hung up. Also, Flamer doesn't do crazy dps, even if the total damage for a full cast is high. The DPS ends up being around 3000 or so to armor. Sounds good, until you think about something like the Reegar, or even more "pedestrian" examples like the Hurricane, Raider, Wraith, Claymore when used on a decent weapon damage character.