One of the elements that make for an "elegant design" in addition to simplicity, low cost, and reliability/durability is "maintainability". Slave cylinders are common replacement items. They rarely last the life of the clutch or transmission, even with frequent fluid changes (but that's not how mine failed as I explained in my previous post), so ease of replacement is important in my book since I keep cars a long time.

Most hydraulic clutch release systems have many of the features you mentioned, but my award for "best design" is the mechanical linkage in my '63 Corvette - simple, low cost, low friction, durable/reliable, and in the event of a problem, easy to access for repair.

The worst is the cable in my Cosworth Vega. The OE routing forced it into an S-bend, which is a very bad idea. After having to replace it at about 30K miles I analyzed the problem and rerouted it in a smooth arc. That replacement is still there, but it needs to removed from the clutch pedal bracket and firewall every few year to run a graphite lubricant emulsified in a petroleum distillate carrier that evaporates (I use Lok-Eze) to reduce friction.

Duke