This sounds like whiteboard space/time is a scarcity you haven't shown to be artificial. (I'm not saying your approach is wrong, just that it doesn't fit with the theme.)
The only concern I have is working with wall-size diagrams on an iPad. There are many architectures and diagrams that have so many parts it simply just takes up a large amount of drawing space to hold it all.
These days, I make do with LiveScribe for my own notes and copy of what is going on at the whiteboard, and an accompanying snapshot of the whiteboard at the end of the meeting to attach to my LiveScribe notes.