And no, dismissing is not learning, but facts are hard to deny.
If it's facts you're after (and I'm aware I could be wasting my time here), based on a TGI specced for weapon damage with full damage overload and level III armour piercing rounds, assault rifle amp and power amp:
A single overload out of cloak will do around 4700 points of damage to barriers or shields, equivalent to 12 harrier X shots (or 5 head shots) out of cloak and in a fraction of the time. That will pretty much fry a phantom's barriers on platinum and take a decent chunk out of other bosses' defences.
You complained you had to hug ammo boxes with the harrier, and there's your solution. Overload plus a quick burst of fire will take down most shielded mooks faster than the harrier alone, and you'll use a lot less ammo against bosses.
Sure you don't *need* overload to make the kit work, the TGI is absurdly powerful with a harrier. But overload will greatly improve your damage against most bosses, and there's plenty of them on platinum.
4 in stim packs and fitness is enough to free up the points for overload. I should add that the crowd control from hitting extra targets with overload is more useful than shield damage for other kits, but I don't find that so important for the TGI.
As for hunter mode, there's no way around the screen overlay of that hurts your eyes. But the shield reduction only applies to base shields, and won't reduce the extra shields from fitness, cyclonics and the like, so Geth kits don't have to be that squishy with hunter mode on.
Hope that helps you see what people are talking about.
Numbers were taken from kalence.