- Diagonal lines are cool because they stand out... can't really comment on that. Have seen such points before on Smashing Magazine, back in like 2007 or 08, where certain elements break commonly accepted design paradigms and therefore standout.
- Illustration/hero image is nice because not too much detail... see this one I feel is force-fitted. You could say that about most hero images and you'd be right.
- Well executed typographic contrast... I'll look at it in detail again. Didn't notice some of those points, as opposed to websites of other funded tech companies.
- Color palate well suited to industry... read those points too, but I'm wary of them because they're like people's taste in wine, music or art.
- Interactive elements giving polish.... YES, this I 100% agree with. The mark of great craftsmanship is an incredible attention to detail and execution.
- Design I mention... just google "best landing pages" and took the first example in the first result.