I'm skeptical of open-sourcing UI and workflow builders.
The upsides are that you enable a community to build connectors and the UI builder + maintain them, but the downside is that you have to manage the community well enough that enterprises can trust the connectors and the UI builder. The challenge of maintaining the community + maintaining some sort of an SLA is very hard. This type of software is extremely hard to test for –writing integration tests are much harder for the frontend than they are for something like a database (e.g. MongoDB) because of the permutations of use-cases). The OSS+managed model seems to have succeeded in areas where very you can regression tests are much easier to maintain and there are clear benchmarks to test the community's output against.
As a buyer (we recently bought SuperBlocks (https://www.superblocks.com/) which is just a managed version of the same idea) it's hard to commit to an open-source version of something like this given the problems above. I may be totally wrong – I've never run an OSS+managed business, and as much as I love the ethos, I still have to not care about the stability of an internal tool builder that my company is being built on top of.
E.g. Stripe had a similar tone in that they basically wanted to maintain their margins but didn't get anything close to this type of negative coverage. No MLK quotes though