As far as doing my research is concerned, I got it from T-mobile on several
occasions that viewing documents etc. would not be a problem.
Is that all you did, though, talked to a T-Mobile rep?
Everything you are complaining about was well documented all over the internet since at least september. Even the information straight from Google/Android was honest about that. Those things were in blogs, forums, previews at Engadget, Cnet, Gizmodo, and all sorts of other places. All you had to do was put "T-Mobile G1" into Google and you would've found that information. Asking reps is a gamble, as they only know as much as they've been told, and with any company there are always going to be reps that will say anything just to get you off the phone.
My suggestion is to always do a lot of research, especially online, before you make a major purchase. Even if I'm not buying something at amazon, I'll look it up just so I can read the bad reviews to find out what people hated. A lot of times people expect something out of a device it wasn't built to do, but in some cases you find out "oh, it has THIS problem, No way man!" and you save your money.
To clarify a few things.
You can view attachments, I've had no problem seeing .doc attachments, and google docs has read-only access to .doc and excel files.
There is a sound recorder. Look in the user guides, they should show you how to get to it.
I think the G1 is the first of a new kind of device. A Smartphone for regular (read Non-business) people. I see 14-year olds with blackberrys and I'm pretty sure they don't even know what exchange is, let alone need it on their phone. People who don't actually "need" a smartphone are buying them for the added features, the web connection, the full keyboard, etc. I think the G1 didn't have exchange support built in because they weren't designing it for business people. Look at the apps that won the design challenge, look at the ones in the market right now, these aren't spreadsheets, and stock-exchange tickers, these are shopping tools, social interaction tools, games, stuff that's for anybody.
But that's just my two sense.