We've had flagship machines for about 6 or 7 years now with few (chopper bearings!) major problems of any kind with mechanicals, hydraulics, or electrical. Started with a 7010, trading to get more capacity since then as we've expanded.
Farmer Jones, I can't let you spread FUD about the Case hydraulics without protesting. The nest of hoses in your picture is actually really simple, logical, of clean design, and easy to trace in just a couple of minutes, because they chose to put all the hydraulic pumps in one place in this design. It looks *much* more complicated than it actually is. Simply put it's about 4 or 5 individual hydraulic pumps (some are stacked) and drive dedicated circuits. It's not a spaghetti mess, and it's not complicated--I know because I've gone over the hydraulics as I was concerned like you apparently are. To the OP, go down to the dealer and have your salesman open the side panel and take a look for yourself if you're concerned. Some circuits are 3-hose circuits with a pressure, return, and case drain lines. The main valve block on the left side of the combine is pretty much the only multifunction valve I can think of. It controls the feeder up down, the auger in out, steering all from the same circuit. The other circuits are all single function if I recall. I can go take a look if the OP needs more information.
Despite your diagram being simple for Deere's mechanical power flow, things are still very cramped under the shields. By comparison it's very easy to access bearings, belts, and pulleys on the Case and things are open and accessible, even the hydraulics. Hydraulics turn out to be extremely reliable. I don't know of any flagship combines in my area that required repairs to the hydraulics. Honestly I haven't even heard of a leak, other than one I had once which turned out to be caused by the hyd filter body that came apart. The only major mechanical repair we've ever done was chopper bearings (the weakest part of the machine). Haven't ever replaced a belt, and can't think of any other bearings on the combine itself we've replaced.
Case combines have their own frustrations for me, but hydraulics has never been any of them.