I haven't got Steve's cute snout or droopy blue eyes so I may rant on occasion, but full HTML5/CSS3 support should go higher up the priority ladder instead of things like bringing back .NET 3.5 compatibility.
With a little effort behind it and some embedded template alternations v4.4 could be fully 'semantic html5-output' compliant, tying directly into end-user wishes and if you're uncertain about it, include a html5-shim to support legacy browsers or take a dependency on Modernizr which Microsoft does as well.
End-user clients demand it, whether it's just latest fashion and eye-candy or actually use full. You can't lead ahead of the standard naturally but the 'semantics' (microdata/section/article/multiple headers &nav sections) that's been finalized and actually beneficial in a Google/SEO way.
Next to that it gives you guys the sales edge towards the SEO guys complaining about not being able to easily do A/B / MultiVariant testing while you guys develop towards that Q1 2012.
If you guys manage to integrate http://www.schema.org/docs/schemas.html
as a new form of taxonomy next to tags and categories you'd even be further ahead of the curve...