I've happily used Zen on about 10 websites over the last few years. However I am now developing an internal workflow system for an organisation ( no requirement for SEO/content source ordering or mobile/responsive ) and would love to try another base theme that doesn't do content source ordering and is easier to understand. All I really want are a good sprinkling of classes and for it to be easy to create new regions. No fancy tricks or clever wizardry required.
Your thoughts appreciated.