Hi,
As far as I'm concerned OmniGraffle is absolutely amazing piece of software for diagramming with shapes and images but lacks some basic text functionality that would really make it solid IMHO.
1) Justified text spacing is egregious. I would love to see something akin to Tex's hyphenation and justification algorithm since it produces such beautiful text flow. In OmniGraffle, the alternation between block os white space and chunks of text kills the aesthetics
http://en.wikipedia.org/wiki/TeX#Hyp..._justification
2) A way to define flow _between_ text boxes where I can type in one and have overflow spill into another, allowing for things like 2-column layouts without the pain of handling the overflow by hand.
I realize OmniGraffle is not addressing the same domain as something like Adobe's InDesign, but so I wouldn't be terribly disappointed if point 2 never happened, but point 1 is crucial for upping the ante on the aesthetic front.