With the R52HN cards throughput up but ccq is down, I believe to date MK 802.11n has/had issues ?
http://forum.mikrotik.com/t/802-11n/28753/1
Not sure if this still is a issue but either way i would stick with a setup known to work like 802.11a turbo, nstreame, adaptive noise immunity, reduce data rates to improve ccq, until n is sorted out, I try to install a tested working equipment configured and ready for install on a hill,
At a guess was the client -76dbm the 5180, and -62 the 5700, if yes antenna gain
A possible option is to have one polarity using r52hn cards and the other polarity XR5 cards, and it follows one polarity N std and the other A-turbo, ??
Thanks for the link
n21roadie