Glass essentially turns everything into a 1 Hit kill instead of just Melee.
The maps are not designed for good cover so there is always flanking fire.
If you have a Fireteam without a Titan (or 2) it gets really nuts.
Most strikes you can't get a good strat going until the 3rd or 4th wipe. Never mind when the enemy fire matched the Singe burn type.
Blackout modifier is a piece of cake next to Glass IMHO.
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Glass is the only modifier that I just say, screw it, I'll play strikes tomorrow. Blackout isn't that bad at all.