A more specific not-quite-gripe: I have a small concern over a couple of things people seem to love. Both the cards (do people love those?) and the alternate activation sequence (people definitely like this) both seem very tacked-on to me. The action cards, especially, are very obviously something thrown in to give us another little thing to buy, and are in no way built into the system (aside from as an easy, unenthusisastic stab at a balancing mechanic). The ganger cards don't do anything a roster couldn't do (bar keeping track of loadouts, whicj is itself a poor rule that exists for no reason), and there's still a need to keep a roster in order to record the gang's information (which is very little and could have fit on a card itself). The alternate activation system is about s basic an implementation as it can be and I expect it to break down fairly badly if stress tested. IIRC it's possible to fit 17 armed members into a starting Escher gang; when Scavvies come out we'll see how well this system works. The reason I never included alternate activation into my own house rules is because I couldn't come up with a system robust enough to deal with scavvies and spyrers together, as well as having a discrete 'end of turn' stage to manage periodic effects. It also doesn't seem to handle more than 2 players that comfortably, which is a shame as it seems like a pretty common way to play Necromunda from the groups I've played with.
If I had time to design something, I'd probably marry the cards with the activation system using something 'inspired by' the game Havana. That is a good game with an ingenious system. Each player has a discrete set of numbered action cards, plays two, reveals them and arranges them into the lowest possible number (so if you play a 2 and a 6, you make 26). The lowest number goes first and takes the actions they chose. Once its all done, everyone replaces one of their cards with another, face-down card. It can't just slot in and would require the system to be fully built around it, but it's really really good.