It would be great to have an optional window displaying all the data records that would be changed upon a sync, whether in the Outlook database or on the synced device. This way it would be easy to eliminate some nasty, unintentional modifications, deletions or duplicate records.
In this window, the user would be able to decide what to do: for all records, or one by one. Have a look at MyPhoneExplorer; it implements this really intelligently.
This would be a very important and big step towards problem-free and reliable synchronization and could eliminate some nasty unintentional/unexpected results.

This window could be set to show up always (during) before a sync so the effect of all the possible settings could be seen beforehand. (Let you check how MyPhoneExplorer accomplish this. It is awesome.)

Lets suppose the following scenario:
The user usually enters new data on the PC Outlook, but mostly never on Android (or doesnt want to retain it usually), so he selects the setting Wipe all records on Android before sync.
Now imagine if he created an important note/task on his Android phone. If he later, when he gets to sync with his PC, is not enough cautious and forgets to change the sync settings, then the important Android task would be wiped.
But if the comparison window would pop-up showing ALL what is going to be changed and in what direction, then he could see and prevent the unintended deletion.
And you also aware of that sometimes an alarm dismiss is considered a modification, so you can easily lose modified and actually more recent data.

Of course the comparison window could be populated with very many items (since it should show ALL the items, whether it is synced one way or the other; deleted because of user deletion; unchanged; or wiped). For it to be more easily readable, there should be filtering or/and sorting possibilities to show only items that are to be deleted on Android; marked to delete in Outlook; marked to delete because it has been deleted at the other end by the user; or there is a collision because the item has been changed at both locations; etc.

All of this would make the whole sync process much clearer in a visual manner.

To get an idea of some comparable implementation of this idea, check the Differences window in this backup software (after youve made a backup and then some file additions or changes, also with modifications at both locations):
2brightsparks.com/syncback/sbpro.html