I don't think that random firepower is bad. Sometimes it sucks, sometimes it's great. I really don't understand the dislike of it. Simple method of representing ork randomness. Ultimately it amounts to about a certain firepower, especially on the onslaughts, who in squadrons of 3 will 70% of the time roll between an 8 and 13 firepower. Then again a cruiser will 70% of the time roll between a 5 and 8 for it's frontal firepower.
Randomness just makes things less predictable, which gives the orks flavor. Some other system would ultimately amount to something similar.
I'm not a fan of new systems, and would prefer an Occam's razor approach, where we would make the fewest changes possible to revise a ship/the fleet in whole, and make as least radical changes as possible. Avoiding big things such as removing and changing completely their racial special rules.
Depending on how well we do here, with a multitude of information harvesting, we could possibly revise minor details in every fleets ships (which is a large demand in the community, and the HAs won't touch it). It has been a desire of mine to do for some time, at least with my local game group, but it isn't something that you can do alone, as everyone has their opinion, and it's always biased. With a group of people to discuss things, and vote on potential solutions/what needs fixing, after a certain set of arguments are placed, then likely you can get the best representation of where things should be. Saving any bias from the equation.
More people always provide more insight and perspective, and especially here, you can find season veterans of the discussion, like yourself Sig, as well as Artagnan, Horizon, and Xisor (what happened to him?).