I think 4) is the lack of QoL. In my playthrough, the game become quite repetitive after 5 holdings. I reached 10 holdings and unlocked multi-holding, but it didn't help towards grinding projects.
I think this game needs some milestone to keep more finance on holding reset.
IMO keeping the HR/IT buymax and keep will be enough. The holding reset should still reset everything in these 2 layers, but the milestones should be kept. Keeping everything in these 2 layers is too OP though.