Estimating real estate appreciation is never certain. Both in general, and regarding the Washington-Baltimore areas specifically, I'd expect continued softness (possible decline of a few percentage points) for the next several years, then a leveling off, followed by nice appreciation. If I had to guess, I'd say someone who buys now in this area will probably see some (but not a lot) of appreciation over 2008 values.
I don't know of any new developments, highways, etc. That's an excellent question. However, keep in mind that in today's economy a new development or mall could well be cancelled. I'm not sure how BRAC affects the area around Owings Mills, if it does at all. That might be something to keep in mind.
My best advice right now is to search for value. If, for instance, you can buy at 20% under market, and even if the market is absolutely flat for the next 6 years, you'll still come out ahead. Even if the market does decline somewhat over the next 6 years, you'd be OK. And if, as I expect, the market will be somewhat higher 6 years from now, all the better.
Hope that helps.