Flash might be garbage, but for sites like youtube and flash games, your sort of stuck with it or else it doesnt play videos or games right? Or is there an alternate way that supports these that I am not aware of?
Youtube has used HTML5 as the default player option since January of this year.
For flash games, can't help you there, since I'm in the 21st century...
. Most of the new features added in the last several versions were largely tracking and DRM 'features', so it is unlikely that a Flash game would require newer versions of Flash anyway, meaning 11.2 should be fine. Very few new games are developed in Flash (thank goodness) anyway, with most games for the web being constructed using HTML5/Canvas.
I have Flash set to "Prompt before activate" always, and seldom activate it, though I get a chuckle when a random site that doesn't need to display any sort of video shows the prompt. Also I've found that the option is pretty much the "default" anyway, as Flash is typically sets to "Prompt to activate" mode by security issues. Firefox and I believe chrome recently changed the default setting to Prompt to Activate because of the rampant security issues.
Shumway is an Open Source project designed to play .swf file formats. This is the format used by Flash Games.
Now that youtube not only supports an alternative (HTML5) but enables it by default on any supported browser, hopefully developers can stop developing things using Flash. Regardless of how easy it is to use or create certain content using Flash the concerns of the user should be more important, and the fact that using Flash for your game/software means your users have to install a well known security sieve ought to be enough to use another technology such as Javascript and HTML5 Canvas.
Another consideration should be to have the developers of Flash games allow their game to be downloaded, rather than require the browser plugin to be installed. The Flash Player install includes a standalone player (or if it doesn't, one can be downloaded) which is a more secure option as it cannot be exploited externally.
