I think we have to stop for a while and reconsider our standpoint. I've used windows systems for ages and AAMOF, I forced to use them at work. On the other hand, I've used Linux systems for years too, and two years ago I decided I would give a shot to Apple products. I can say I have some IT experience with enough knowledge to form my own opinion. So far I've ditched every non-Apple product that I owned except from my QNAP NAS, which I plan to ditch too when I finally purchase the mini...
After these two years of using Apple products, I would say I've reached to a few conclusions. Among them, I can tell you that if you expect total flexibility from apple products, you should not chose them. They are designed to work in several specific ways, and expecting to modify that will end up in frustration sometimes. Apple products are mainly designed to make their users' life easier, but for that they have to make some concessions to they eyes of more technical people like us.
Instead of keeping on reading stuff online about fusion drives and so on, I think I (and possibly you) should reconsider what I (you or we) don't like about Fusion Drive. I don't like to know that the OS will continuously spin up the hdd even if eventually the data will not be placed on it. I don't like to lose control over where files are to be placed. It scares me a little to also lose control over how the drives are organized, etc., but something inside me is also demanding I stop investing time into this, and hand these decisions over to them, and flow with it.
I know it may sound a little irresponsible, but I've had this revelation. So, as long as I can determine what are the things that bother me about FD, I can possibly let go of the control, and simply make sure I keep my backups current.
In 2010 Steve Jobs said that the new MacBook Air gave shape to future MacBooks. Something similar maybe hiding behind the FD, and I imagine that technology is soon to be found in the rest of the lines. Are we ready to flow with it? Care to help me outline what bothers us about FD expanding on what I stated above?