1800 crit is way low... I have mixed gear - some slots DPS and some tank (using shield , not focus). 2.5k medal in every match is a given. Usually off Assassinate that can crit as high as 3.9k (of course, by that time, the target might not have that much life left) or adrenal+relic+energize Shock (have seen that crit for close to 3k, mostly it stays in 2k-2.5k range).
That said, I rarely break the 300k mark for a WZ and only once have I gone above 400k.