I rather like Wikidata and see a lot of untapped potential in it. In contrast, WikiLambda feels like a fully utopian project. I already shudder from the complexity of a medium to large MediaWiki template, and I'm not convinced this system can be expanded into a full programming ecosystem - one that's supposed to cross the bridge to natural language too.
As far as i know, wikilambda isn't really based around the mediawiki template system. And the mediawiki ecosystem itself is turning away from complex wiki syntax templates to lua based templates.
Regardless i do agree with you though. WikiLambda/Abstract wikipedia feels like second system syndrome to me.
WikiLambda is what happens when someone looks at the definition of the second-system effect and says, "Hey, that's cool and all, but I bet I can make a bigger, better version of this."
"The Search for the Perfect Language" is a really entertaining book if you like codes, languages, occult history, and/or chuckling at hubristic academic endeavors.
Umberto Eco is a wonderful writer, up there with Borges. They shared a deep philosophical interest in language, exploring it from various angles in their works. Both widely versed in obscure literature, approaching it with wit and humor.