I know that feeling all too well. We definitely need more choice and more robust theme support. Hopefully this experiment will at least give people another option. I’ll also say that I’ve learned a lot in the process of diving in up to my elbows for a day. Now that I’ve done it once with some reasonable results, perhaps I’ll take a crack at a few more? I still want to take a crack at upgrading the new Twentytwenty theme and helping someone like the brilliant Anders Norén understand them better.
I will say it’s a much easier process with more modern DRY themes which have fewer places to look/check. A reasonable WordPress developer with even a passing knowledge of microformats should be able to convert a pre-existing theme in about a day barring any bizarre coding irregularities in the original theme.
I’ll try to document most of what I’ve learned with some code examples and snippets on this theme shortly so that others might follow along or make their own modifications.
I can’t commit to doing it personally, but perhaps people might try adding links to popular/useful themes to https://indieweb.org/WordPress/Development#Themes as suggestions for developers to spend some time on updating/converting?
I specifically chose Twentyfifteen because it’s big, popular, fairly simple, and robust, but it still has some flexibility in terms of changing the look and feel by using small things within the customizer. I think it’s also a very good, basic template for a personal website. I may take a look at some others in these areas for similar reasons.