EC explains how the current progression system is flawed

[Zfz]

I got to about 1:30 and they started talking about WoW talent tree system. Then I checked the date of the video and saw it was 19 Aug 2015. That was enough info to tell me I didn't need to watch the rest of the video.

When a 2015 book talks about political systems and use the Roman Empire as an example, it is still as relevant as ever. It is talking about an actual example of a talent tree, and the (even though old and no longer in use) WoW talent tree system is one that is very widely known and one that has been experienced by a lot of potential viewers of the video, hence a good candidate to use as an example.

If the video was titled "a sample of current MMORPG progression systems" then your reply is relevant. But that isn't the case.