jgresham: Yes, but they still provided a DRM option, and required extra money for it - they didnt simply throw it in, it required a $1 donation. My point was merely that Humble bundle clearly didn't have an ideological issue with working with and providing games on Steam, so it is not a huge departure.
Wishbone: If you don't think that "Steam-exclusive" is a huge departure from "DRM-free, redeemable on Steam", then I don't think there is any point in discussing this further.
Quick question - how many of the games available in the earlier bundles were not already available elsewhere as DRM free, and how many of the games in the new bundle are? If THQ doesn't produce DRM free versions anywhere, I hardly see them doing it solely for HB. This could therefore be framed as a technical limitation from Humble bundles point of view, just like not being able to offer all their games on certain platforms.
Am I in favour of them all being completely DRM free? Of course. Do I think it is a step away from their usual deals? Yes of course it is - and no doubt the major publisher swung a big bat there. But the Humble bundle was clearly up for working with Steam as a distributor before this deal came through.