Two things:
a) Regarding crossovers it'd be also fun to see the LA team again interacting with either Five-O or Magnum PI or even SWAT (if the last one is in the same universe as NCIS).
Magnum PI is in the "same universe" as Five-0 meaning that they'd appear in NCIS as well
b) Shouldn't Arkady have his own thread? I mean he appears at least 4-5 times in each season (and he's hilarious) or a general thread for the Russians of LA?
(Just a quick thought)