FPGAs with Feedback issues

Here is how I would rewrite your paragraph (rather significantly):

FPGAs are programmable devices that allow you to create custom logic designs in hardware without the need to build an ASIC or use multiple chips on a board. They can be reprogrammed with the same or a different design "in situ" at any time. You can simulate an FPGA design in a simulation tool, but that design can then be implemented with full functionality in the FPGA. An FPGA design is created, compiled, and programmed using the manufacturer's software. This is especially important to engineers creating novel circuits because they don't require any other hardware on their board to implement the circuit other than just the FPGA. FPGA designs are typically created in a hardware description language (HDL) to describe the behavior of the circuit and then compiled by the design software. The design software has many debugging tools to help with everything from creating the initial design all the way through testing the design while it's running in the FPGA.

Side note: while FPGAs can be used for ASIC prototyping (which I think is what you are thinking about here), this is not a huge part of the development base for these devices.