Agree the icons are unnecessary and silly. Apple should know better.
The corners haven't bothered me much, I like seeing a bit of a gap down there, and I haven't had issues dragging it but that could be because I'm using a regular USB mouse and not a trackpad.
I've been a macOS user (or OS X rather back then) since 2003. It was truly a blessing to finally get a proper UNIX™ on the desktop. I was on Linux in the 7-8 year period before that.
Everything after Snow Leopard has been downhill in my opinion :3 macOS still my favourite unix but it started feeling is no longer my unix anymore, I'm just a glorified tennant.