> 1) is it possible to use Obsidian like Logseq, with a primary block based system (the block based system, which allows building documents like Lego bricks, and easily cross referencing sections of other documents is key to me) and

More or less yes, embeddable templates basically gives you that out of the box, Obsidian "Bases" let you query them.

> 2) Don't you expect to be sherlocked by the obsidian team?

I seem to remember that someone from the team once said they have no interest in building "real-time" collaboration features, but I might misremember and I cannot find it now.

And after all, Obsidian is a for-profit company who can change their mind, so as long as you don't try to build your own for-profit business on top of a use case that could be sherlocked, I think they're fine.