IE + video plugins is a ticking time-bomb, and since it is no longer developed the ticks are getting quicker.
The biggest threat is IEs lack of ability to load plugins only if clicked on. You have no choice but to let all the plugins run when you open a page.
As it is no longer developed It is falling behind in HTML5/CSS3 support, so as you go down the road many newer WebGL players will not be compatible.
I have this problem in old Opera 12, so Firefox is my browser for some modern sites.
Hardly any people make extensions for IE, so you probably can't replace the functionality like other browsers.
There used to be some activity, but I don't think there is even a still developed UserScript addon.
TrixIE looks like your best option there
https://sourceforge.net/projects/trixiewpf45/
With a "Greasemonkey" type addon, you can make sites behave or look different, by using "UserScripts".
eg. I use one that makes Youtube use the VLC browser plugin, and one that gives me a volume control on Bandcamp !
https://en.wikipedia.org/wiki/Greasemon ... r_browsers
If you want a more secure/private version of Chrome, try the builds made by Avira
https://www.avira.com/en/avira-scout
or a more configurable/customisable build made by Vivaldi
https://vivaldi.com
Both are more private than the default Google build (that loves to chat back to base all the time, watch your keystrokes, and hog 50% core and 250MB RAM while updating, even though you didn't run it yet).
Currently at this point of 2016, IE has 786 known vulnerabilities, and most of them are via video plugins, because they also have the most vulnerabilities.
https://www.cvedetails.com/vulnerabilit ... lorer.html
The year is just over half way done, and IE has more than tripled the amount of "CVEs" since last year.
That is one leaky boat to be sitting in !
Firefox is also full of holes, but has an active upgrade cycle and there are many addons that help to negate security and privacy problems.
Total critical vulnerabilities 2015
Browsers
Software
