There is nothing inherently wrong with using FPGA's. Especially if you're doing a product for release into a limited (or unpredictable) market. FPGA's though more expensive than custom/ASIC circuits don't have the same set-up charge & minimum order quantities that ASIC's have - so in that sense the choice of FPGA made sense.
I'd probably have gone with Antifuse components (like QuickLogic's) rather than SRAM based reprogrammable units (in that Antifuse ones are "instant on" and don't need configuration ROM's like SRAM FPGA's do).
This would (however) mean the FPGA would behave very similarly to an ASIC (and once programmed could not be altered). The whole point of using FPGA's should *not* be just to allow half finished computers to be shipped and then "retrofitted" by a reprogramming job - but rather to allow manufacturers to produce short runs with limited risk and lower cost. If the system proves a success they should then be able to switch to full ASIC's which still have some speed benefit over FPGA parts (and once you start shipping machines in larger numbers ASICs finally *do* make economic sense).