To me the point when HL2 shit the bed is when they pulled a Bioshock Infinite and fell in love with a gimmick...the gravity gun. In HL2 the GG was just another weapon, used in a couple of spots but other than those spots it really wasn't required. What did we get for EP 1? Gravitypaloza. By the time I was being forced to shoot basketballs at striders I was just sick of the stupid gravity gun, just as I got sick of infinite shoving that damned skyhook under my nose going "Isn't this neato"? Sure it was, before you BECAME ANNOYING ABOUT IT!!
As for so many games not played? Bundles, simple as that. You can get so many bundles on Steam that you soon end up with dozens of games and you only have so many hours in the day so...there ya go. Between the big Steam sales and Humble Bundles I probably got a good 50 games in a couple months, just not enough time to play them all before the next killer bundle comes along.
Finally as for Steam being "bloated" on OSX.....ever stop to think that OSX simply isn't very well suited as a gaming platform? Because on Windows you are looking at maybe 60Mb (I have Raptr AND Steam running and barely am using 100Mb) and from what I understand the Steam for Linux also runs quite well, which leaves OSX looking as the culprit from where I sit.