Well, there's been a ton of feature and bug work on the mainline since the release of 4.0(1) - the best I can suggest is to puruse the release materials for the 4.0(2), 4.0(3), 4.0(4), 4.0(5), 4.1 and 4.2 releases to see if any of it turns your crank. You can see the release trainingn materials including training videos for TAC and other materials on the TOI pages for the releases here:
http://www.ciscounitytools.com/App_AlphabeticalListing.htm
Things like a completely reworked digit handling scheme which allows for very detailed timing edits, custom key maps, additional conversations, a new optional reworked send conversation, customizable subject lines, Broadcast messaging support, multiple switch integrations added, dropped call recovery, many per user conversation options including different conversation styles, key mappings, prompt and messaging speed control etc...
Aa _lot_ of water has gone under the bridge in the years since 4.0(1) went out the door...
