Except it's now turned into "pay what you want as long as it's more than average"; to which I automatically responded by paying $0.01 more than average instead of my usual round $20...

No. It's still pay what you want (although I think there's a min req of 1 dollar for getting steam keys)

You have to pay more than the average to get the 'extra games'. I'm pretty sure they've had that since the beginning

Nope, the first ones were "pay what you want, get everything" (with the first bundle retroactively adding source code releases for everyone no matter how much they paid, and the next adding extra games half way through the week, again for everyone).

"Pay what you want, the more you pay the more you get" is still technically "pay what you want", but it's a slightly different meaning than the original.

ED> Also, with regards to the $1 minimum for Steam which seems to have become a permanent thing:

"The Humble Indie Bundle 4 overlapped with a large holiday sale on the Steam software service, which offered numerous prizes by completing some achievements associated with the offered games in Steam, including entries into a raffle to win every game on the Steam service. During this overlap, Humble Bundle found that some users were abusing the system, paying the minimum amount ($0.01) for the Bundle, registering new Steam accounts, and using the newly purchased games to improve their chances for the Steam raffle. Humble Bundle considered this "unfair to legitimate entrants" in the Steam contest, and to stop it, the company altered the sale so that only those who paid more than $1.00 would receive Steam keys for the games"