That's your personal experience and personal experience depends on person and project. I had more than 3 months to work with pretty big ng1 codebase and I'm still unable to wrap my head around all these "@", ">", "=" and all ng1 cryptic syntax for property-binding.
At the same time I dived into ng2 easily (with prior RxJS and TS experience, though) w/o any guidance. Much easier than e.g. Ember.
Of course, ReactJS was even easier than ng2, but for any big app you'll need redux, redux-thunk, redux-middleware and all other bells and whistles, which makes actually learning ReactJS.
And after several years, saying I program in React will not mean anything, because do you use flux-saga (not a real thing, probably) or redux-thunk? And with Angular2+ there will be only one type.
Ng2 might never reach popularity of React, but it will have its niche in Enterprise world.
I'm front-end guy and I'm missing the problem with that article. Arguments in article seem reasonable, what's wrong then? Does he generalise one example of bad middleware code to all middleware or is that code even okay and he misses on the idea of middleware?
I don't think Oracle by itself is a problem, but the article says nothing why we should use that technology, hiding a link to the site deep in the article.
So according to Oracle's site it's just another Universal Toolkit for web & hybrid mobile.
And the problem is... they're late for this game. While technology might be OK, it will never enjoy decent adoption by community.