Exchange/ Outlook rules handling can bite you in many ways.
Before you proceed, export all your current rules into a file.
You will need it!
Read the following article to have a better idea about Exchange server-based and client-based rules
This talks about the Exchange rules storage limit of 32K:
Some workarounds for this 32K storage limit problem
For the advanced,
Bruse Heimbigner has a suggestion of using some programming technique to workaround the 32K storage limit problem: