When you are going through your inbox wouldn't be nice to go directly to the Sender's ACT Contact record with one click. This would allow you to then proceed to do a number of different ACT things without doing a Lookup. I find myself doing this numerous times throughout the day.
The solution would be a 5th ACT icon in Outlook that would act a lot like Quick Attach but would perform a lookup on the highlighted email(s).
This would work particularly well for those of us with dual or wide screens where our day is spent in both the Outlook Inbox and ACT with both applications open.