So I decided to mark this as an answer because there doesn't seem to be a way for the user to improve things when watching Twitch in a browser.
After further research, I found for myself that it's more feasible to look for other methods to mitigate Twitch's poor performance overall.
Here is the alternative method which makes it possible to watch a video stream in VLC.
I found this guide on xmodulo.com, initially via linux.com:
FIRST THINGS FIRST
You can paste into the terminal via Ctrl + Shift + V. This should make life a bit easier for you, when you just want to start it up real quick. No need to type it out or use the mouse.
Twitch supports timecodes! You can start a video at the 4th minute by adding
?t=4m at the end of the URL.
Livestreamer is a command line interface (CLI) client which, upon given a streaming URL, retrieves live streaming video from the URL, and pipes it into a native video player running on local host. So with Livestreamer, you can enjoy live streaming from various sources via a much stable and lightweight video player such as VLC or mplayer, without opening a web browser. Currently, Livestreamer supports streaming from over 20 different web sites including Dailymotion, YouTube Live, Twitch/Justin.tv, Livestream and UStream.
Install Livestreamer on Ubuntu
$ sudo apt-get install python-pip
$ sudo pip install livestreamer
By default, Livestreamer attempts to pipe streaming video into VLC player. Thus you also need to install VLC player on your Linux system:
$ sudo apt-get install vlc
Watch Live Streaming from the Command Line with Livestreamer
To watch any live streaming channel/program, first obtain its corresponding URL from its official site.
For example, let's say the URL for the live streaming content that you want to watch is
To check available streaming quality (i.e., bitrate) of the given content, simply run livestreamer command with the URL:
$ livestreamer http://www.youtube.com/watch?v=Vw4KVoEVcr0
The output for that is
[cli][info] Found matching plugin youtube for URL http://www.youtube.com/watch?v=Vw4KVoEVcr0
Available streams: 144p (worst), 240p, 360p (best)
To watch a live stream in the best available quality, run livestreamer command in the following format. This will automatically launch VLC player, and streaming will start on VLC:
$ livestreamer http://www.youtube.com/watch?v=U4Pw3ofFWgs best
To watch a live stream in specific streaming quality (e.g., 360p), run livestreamer as follows:
$ livestreamer http://www.youtube.com/watch?v=U4Pw3ofFWgs 360p
If you have your own favorite streaming player, you can let Livestreamer launch the player instead of default VLC, as follows:
$ livestreamer --player=mplayer http://www.youtube.com/watch?v=U4Pw3ofFWgs 360