I can't agree with you on this topic. I like the thing HIB does to linux gaming and open source community thus I would like to donate them a bit of my money. On the other hand I really can't understand why had they offered a "bundle" consisting of one single game. Giving games from previous bundle in case you pay more then the current average isn't an excuse - I already have them all as I had bought every previous HIB I was aware of. So the only thing they achieve with offering solo game "bundle" is getting less money then they might get in case they would offer normal 4-5 games bundle. I had bought "Frozen Synapse" HIB for myself but I only paid $5 for it and my "split" was mostly into HIB cap. For comparison I had paid several times more for previous 3 bundles and had really enjoyed playing such beefy titles as World of Goo, Machinarium, Cogs, Crayon Physics, And Yet It Moves, Braid and Osmos. Hadn't had enough free time to give other titles from older bundles a try.
To make it short: if you offer a bundle - it should be a bundle and it shouldn't be significantly worse than previous offers of the same kind.
they state it's only worth 25$ (which is what ~£10?). That's less than I spend on a pizza