BuShips ... Yep, I'm SeattleGamer anywhere I post (haven't run across anyone else already having that account yet). I've seen your posts on TMP

As a fellow Washingtonian, I bid you greetings!
I have long been a fan of the slotted base, beveled edge look. I mount even non slotted figures on slotted bases. So I liked the originals shown in the first set of photos. One of the things you can do with a beveled edge is put some sort of marking on them (one small dot for 1st squad, two dot's for second squad, a chevron for the sarge, etc). With flat bases (usually people go for fender washers) there isn't much of an edge, to you can't do that.
However, I don't think the thin bases are bad, and I know LOTS of people like that look. They are not my first choice, but the new thin bases wouldn't stop me from getting the minis. It's all about the paintjobs.
Larac ... yes, scale creep has been going on for some time. It's odd too, because wheny ou think about what "scale" is "supposed" to mean, it should never happen. The railroad enthusiasts never, ever have to deal with that. Why? Because railroad scales are set in stone, period.
I do remember that way, way back (1977 or so) when I first started playing D&D there were all these 25mm minis, and 1" square was 5' when you drew your maps. And for that reason, in my mind I always figured "Okay, 1" is 5' on the ground, yet a typical person might be 5'10" - and adding thick boots or whatever, maybe a good rule of thumb was 6'. So why is a 1" tall mini a 6' adventurer, yet 1" on the ground only 5'?"
And things have only gotten further apart since then. Eventually "Heroic 25mm" became simply 28mm and it's own scale. And now, there are lines of minis (like SST) where they are really 32mm tall or more. That's far enough of a difference to not mix well in my mind.
As for doorways, 1 3/4" is probably a safe bet - or close enough to be fine. If these minis are actually 28-30mm tall, with another mm or two for the base height, a figure standing next to a 1 3/4" door won't look like they need to duck, and that's really all that matters.
I have a bunch of cardstock buildings (Worldworks Games and Microtactix and even some I made using Fiery Dragon textures). The typical door is 1 1/8 - 1/1/4" tall and that works for me. Even though I use 28mm minis, and those are mounted to slotted bases adding another few mm, it's close enough to work. They don't look like giants standing next to a door.
Steve