Many years ago I had the opportunity to work on a new project that involved embedded Linux and FPGAs. As the "Linux software person" I worked entirely on the Linux software. But I had the good fortune to work with some brilliant FPGA people. I was blown away. It was amazing to sit down with these people and say "I could really use a register that works like <this>" and a couple hours later be emailed a new bitfile, load it in, and find a register that did exactly as I wanted! Brand new, custom designed hardware... on a whim! The development of the product progressed hand-in-hand in this way, and it was a very successful endeavour!
My thoughts regarding hardware are similar to how I feel about HDLs. I would rather become somewhat knowledgeable on a bunch of them rather than to be good at only one. Also, since I do all my development work on a Linux machine, one thing that will be important for me is how well the development workflow of the various vendors supports Linux. How easy (or hard) is it to develop for vendor A's product in Linux (including getting the result into real hardware) versus vendor B, C, or D?
FPGAs have always been an interesting and fascinating technology. Coupling them with Linux in an embedded environment, I think, is an amazing partnership. Linux is great, and real-time Linux is amazing. But, let's face it, nobody can realistically promise absolute strict timing as long as a software scheduler is involved. When done well, using an FPGA can cover those things that absolutely need very strict timings. FPGAs also provide a decent place to "hide" the magic sauce of your project. Also, with good profiling, it's possible to find those processing-intensive parts of your design and potentially move them out to hardware.
I think FPGA companies have sold as many FPGAs to EEs as they're going to. Their next wave is going to come from software developers :-)