Is it recommended to use Mac wifi sharing for long periods of time?
The Internet Sharing "hotspot" feature does work well for this. However, it is WEP only and you are stuck with the default IP address range unless you do some hacking. I use an Airport Express and I find it's very convenient, supports "more" secure connections(WPA), and is configurable. It's also always available, never goes to sleep and never drains a battery. It can become a pain always having to have your MBP available for your iOS devices.  

Being in an University environment, I would want to use something a little more secure then WEP.

Also, you can adjusts the signal strength on the AE. Turn it down if you'd like it to just cover your room. Turn it up if there is a lot of other WIFI going on. I'm not sure what kind of range you'll get on the MBP and how many connections it will handle well.

The MBP will work in a pinch. I'd get a dedicated device to save yourself time, and hassle.