At the end of the day BB has a WIDE range of policies that enable your IT department to lock down the device (as you've found). Often these make sense as they allow the IT dept to control the usage of the device - sometimes you've got a control freak dropping in policies cos' they can.
It all comes down to 3 things: -
1) Size of company - the larger, the tighter the policy (IMHO)
2) Need for external regulatory compliance - sabennes oxley et al
3) Cost Control..
Out of your list of 'issues' I'd say the text messaging thing is a little lame as it's a great device for texting..plus with the logging on 4.1.2 you can log every text message sent (and content thereof). The email thing might be there to ensure regulatory compliance...whilst you might not want to text commercial stuff to a 3rd party via your prosumer account, other people might...
Have you tried asking your admin nicely over lunch or a beer - you might even find theres different policies in place for different user groups - and so you could get added to a less restrictive IT policy group?