Looks like a very solid mid-high end streaming build, though you may run into problems if you turn on GSync. It's a proprietary technology, and tends to break things when livestreaming. Leave it off, use vsync.
Other important information: Where are you streaming to? If to Twitch, are you a Partnered caster? If not, exceeding 2000kbps is not recommended, to maximize your potential audience. A 720p@30fps stream on x264 Veryfast fits into this bitrate budget nicely, and with that CPU you can turn down the preset to Medium or lower to use better compression, and make the stream look even better. The 5820k is capable of encoding 1080@60 Veryfast video though, so it has a lot of room to grow, when you do.
Unless you're an established caster or professional player, DotA2 is a very saturated game, and will be very hard to start growing your channel and community with; simply due to the sheer number of newer casters playing it, getting any viewership can be more or less luck, and retention can be low for the same reason (wide field).
Absolutely play what you love, but you'll have better luck if you play something you love that isn't in the top two rows of 'browse by games'. :)