PS is a creat tool or add-ins to Exchange, but making that as a only tool for world wide is a bit strange idea. Like, would you like to do your day-to-day operations using the scripts only? E.g. rename single user? What is the benefit to use PS for that? Before you shoot me because of "...a only tool...", keep in mind that there are tasks which are available only for PS.
And when you step one step back and look your environment more wide, do you really say to your helpdesk people: "This the power shell, this is your tool.."
Or think about your user admins, to create a new user you could ask them to use: Exchange GUI, Exchange Shell or ADUC. But:
- To create mailbox you have to use 1 or 2, not 3 at all
- To enable OCS service, you have only 3 (with OCS add-ins to ADUC), ok 2 might work as well, but it is far away from "efficient and fast" -way.
- Modify user, you have to use 1 for exchange stuff and some basic user attributes, 2 for most of the attributes but you have to remember quite much to do and again "efficient and fast" is a question, 3 when you need to modify some other attributes from 3rd parties.
So as I told, PS is great help in case where you need to create 100s objects at one time, but I doubt that there are many people who have to do this weekly. Also it is great help for creating new databases, but still I'm not sure would I do so e.g. if I have setup server early 2008 and I have to create new database in late 2009, I feel GUI -way is more simple to remember, personally.
And I feel that memory is one issue as well. The commands which you are not using monthly you might forget and you have to put extra effort to find the way to run it. On the GUI even you don't perform some tasks daily or even monthly, you can still see them on the list and find them much more easily.
And personally the worst problem is programming, have you ever tried to write code for managing the objects (create a new user with mailbox by C# or VB). Why to do so... you must re-read my comment and find the reason ;)
On here I can say I'm a bit old fashion....or as others might say: lazy to learn new stuff? :-D