Clojure has futures, lambdas, streams, a community-maintained java.time library, core.match, and Clojure records. I'm sure there would be benefits to adopting the newer JVM-native equivalents, but I'm not as sure they're worth the costs.
Communication "style" and slow pace is frustrating sometimes but that's a small price to pay for all the positive facets of the language/community. I used to be more critical of these but I don't care anymore, the community is wonderful, the language is very usable and thriving, that's what matters ultimately.
About Datomic, I still don't get why there's no push to open-source the on-prem version, especially since nubank acquisition. I dug onto the internals a few times, contributed to some of the alternatives, read/viewed pretty much everything about it and used it for fun in toy projects, and that thing is just so versatile it makes me angry it's not more accessible and as a result not more popular. It has an incredible untapped potential. Every conj I am holding my breath hoping for a "one more thing" announcement where they'd do just that. The "alternatives" do things either quite differently on too many aspects or lack traction.
The "closest" to datomic is datahike right now. Crux/datahike/datascript/asami all use datalog in some way or another but they cover different use cases.
Lot of open source contributors have leave the community, because there is any plan on Clojure. I guess that Rick Hickey is happy with Clojure as it is now, and this is the way is going to stay. And still no Java 8 support for CompletableFuture, lambdas interface, Stream api, java.time, no pattern matching, java records, this group feels like a group of old programmers stuck at Java 6 that cannot move forward.