@MonsterGoBoom Many people who use YouTube never even actually see or use the homepage - they might access the site through a link on Facebook or that their friends send them, or find the site in another way (I'm sure you know people who use YouTube like that). Users like this watch a video, then leave. They might never even choose to use the homepage, and it's definitely possible to use YouTube without ever hitting it or knowing it exists, and thinking that the Watch page is all there is.
One thing the new homepage does is put an emphasis on adding channels and subscribing to them, with features like the big Browse Channels button, the entire browse channels menu, and the channels navigation on the side. Based on what we've seen, with changes like this, more people are logging in, subscribing and building their homepage. Hopefully that means that some of the users who weren't taking full advantage of the site are now.
We made these changes because we wanted to improve on aspects of the homepage like this, some which we feel like we did address to some degree. But I'm well aware there's plenty more that we haven't addressed. Other things, like how content appears on the page in the form of the feed stories, are features that need more tweaking and we'll continue to work on. There's a lot of work to be done on the page, and overall, the page will continue to be improved on - by the end of the year, I think you can expect it to look pretty different than how it does now (hopefully we can have something like or better than an X button by then).