Hard to say since every tool out there moves very fast and we're just building what we think our users want. Overall my personal opinion is the "pull request" model is flawed for businesses but great for open source. Phabricator doesn't serve two masters in that regard. This means we focus more on developer efficiency and code quality. Tools like arcanist are harder to convince people to adopt, but save me personally a few hours each week. (Arcanist does pre-commit lint, unit, and patch emitting). Other tools like Herald (business actions!) and Owners (claim you own code!) are also highly useful at scale.
I don't know. The homepage of Phabricator doesn't give me the impression the developers take the task of building a corporate collaboration tool very seriously.
Sounds like you might prefer the Serious Business Edition(TM) [1] of Phabricator. I don't fault them for having a little fun/being irreverent (or as they call it:'flavor'), but it's a config setting you can toggle on your deployment, seriously [1]
Not sure what you mean, I've always billed it as an internal tools platform since it's our intent to have it do everything you need. (bugs, repo, review, kanban, wiki, chat, etc)