With a 10 marks gets you 20 mats trade, and a 50 mats gets you 5 marks trade, 200 Vanguard marks->400 mats->40 Crucible marks (or one would presume shifting 200 Crucible marks to Vanguard marks). I'm not sure that shifting marks at 5:1 is that game breaking. Please explain. I'd also argue that Crucible marks are more valuable. There are five vendors that take Crucible marks (2 crucible + 3 faction). Only two vendors take Vanguard marks (your Vanguard rep and the Vanguard outfitter).