You know they have totally redone the hammer UI, and you don't have to re-learn everything. It looks very user-friendly, and that was their goal for Source 2.
Dude, you're so deep, I can't see you anymore. On the other hand, HL3 is referenced in the latest Dota 2 update; not much more people will pass away without playing it hopefully.
I'm playing it right now, even though the graphics aren't top-notch nowadays, it is still a fantastic game in this day and age. I love every ascpect of the game and you should really play it, as it only costs a couple bucks in a sale.