1 - You don't understand the former issue or its fix. The issue was that each B4 would reset the timer 5 seconds less than last, as it does now. However, using Enochain while it was still up was the same as casting B4. Since the patch you always get 30 seconds from the ability

2 - Unrealistic

3 - 15/30 seconds is unrealistic, but I could see them upping them to 12 seconds

4 - Flare nerf wasn't that huge, but it was pretty pointless

5 - Useless skills are useless, I'm fine with them not taking up space on my hotbars. And I use lethargy and aetherial manipulation frequently.