Our players were using a lot of the drawing features to mark up spells/etc. They generally had problems that their drawings made it hard to select their tokens. Furthermore, when using it for writing/etc, you get a lot of little fragments of lines (using the freehand). So I'd suggest:
- Players have access to the Text tool (I'm not sure why they don't, but my players say they don't have it)
- Players have a special layer for their markup so it doesn't interfere with tokens.
- One player suggested a Google Earth-like pin feature, where you can place down a pin and associate a note with it, so that the text doesn't sprawl across the map but the info is still there.