I agree with MEC2 coming from a mostly pure Exchange background (alot of OCS now also). I have worked in Exchange PSS, consulting and internal IT for mainly very large companies (over 100k seats)and I hate HAVING to use powershell for most things. It is just not intuative like a GUI and makes a lot of simple things more complex as mentioned in other posts here. PS should be a compliment to the GUI so you can do things that could be easier in a batch but not the primary way of administration. I love learning something new but the technet and other documentation is not always completly acurate for the commands (missing an -ID criteria, etc..) and can get very frustrating when just trying to do some things that have beenshould be easy now in a GUI. I am guessing it was either a code freeze time frame issue or a way to keep developement costs down and not just a lazy dev team.
I hope MS will take the feedback they are hearing from lots of people who have championed Exchange for years as completing the GUI will not hurt the product, only improve it.