A heirloom has nothing to do with it, that just means its seeds create fruit true to the parent fruit.
I have taken some really tasty hybrids and grew them back down into a heirloom of sorts. I've started to grow tomatoes 5 years ago. http://unturf2.tumblr.com
That said, yeah we don't need to engineer the flavor back into tomatoes, we need people to vote with their wallets.
Uh, plant patents are one of only a handful of patent varieties (in the US), and they exist specifically to cover new breeds. This is very much a patent-able breed, and much more easily enforced because it's a well characterized bit of law, whereas the 'gene patents' only got by on a technicality of requiring cDNA intermediates.
I'd much rather have one heirloom than 4 identical red tomatoes still on a vine sold in a plastic box.