So, I've played BFG:R Orks today, with a bit ofadded modification [mostly taken from 2010 ork klanz list, plus that every cruiser can buy one upgrade from 2010 ork klanz. current bfg:r file seems to miss few of them.]
Against Tau. Seeing that Orks struggle against massed ordnance, throwing them against swarms of Tau bombers seemed like a good idea to test them.
Orks lost horribly, of course (in the name of science!), but I have few conclusions.
First of all: despite suffering against ordnance, ships with turret upgrade [from 2010 ork klanz list] are able to hold off bombers for a while. This is a good sign.
Ones without the upgrade just fall apart, though. Allowing every cruiser to take one upgrade was a good tep forward, but I think we should consider allowing them to take more. Otherwise, +2 turrets [or d3 turrets as an economic variant, I'm not sure if I like it, though... sometimes its 10 points doing nothing] seems like an obvious choice against any fleet able to take reasonable amounts of attack craft.
If a player decides to overload on upgrades, he gets very expensive ship, so i don't think taking multiple of those would be that broken.
With +1 ld for numbers, and +1 free escort for low Ld [from ork klanz] escorts are generally solid. They might not require further modifications.
Swapping Ld between ships, coupled with squadron rules and numerous re-rolls make their low Ld a bit less of a problem, though I agree with idea of 1/2= ld6, 3/4/5= ld 7, 6=ld 8 ld table. No amount of re-rolls can make ship with ld5 work, and even 6 tends to be problematic.
Additionally, as i mentioned before, cruiser cap needs to go. in about 1500 pts up, you start to run out of cruisers slots. Assuming you don't take any lite cruisers - if you do, you hit the cap even faster.
One more thing, a bit more.. radical. I'm starting to think orks need a bit more concentrated firepower... With their short ranges and mostly gunnery table weapons, they don't really benefit from having multiple targets from different fire arcs - amount of dice you throw at them is too low to count on any result, in most cases.
I'd consider making some of ork ships' port/starboard weapons l/f + r/f. Needs further testing, though.