if an amiga has not enough backward compatible cpu to satisfy your needs, it could fall back to, then its not gunnars fault. its likely that if if there will be hardware available, there may appear some alternative cores for it.
so far there always has been a lot of talking about fpga for years but very few people who actually did anything. not sure if there is an alternative for gunnars solution any soon, alas. which is uncomfortable, because there is a bit too much of what depends on one person for my taste but i dont see no option.