Personally, I was disappointed in d20 Past

I was really looking for something that had a bit more crunch in it, like a good dozen advanced classes depicting roles from history and maybe a more comprehensive list of equipment for various eras. Over at the WotC boards, there was speculation of d20 Past being a series of supplements which, if it were formatted right, would be a great thing.
If WotC would've broke down the timelines as blocks and made books around them, I think people would've liked it better. For example, covering the 1500s to the 1600s, a 96 page book could detail a good amount of information. Then make a second book covering the next block and so on. Include important Advanced Classes, Feats, Occupations and equipment, as well as essays on important rules for the time (sailing, exploring, etc).
d20 Past read like it was a rushed idea ... which is too bad as it had a TON of potential to be something cool