[{quoted}](name=Valkyrie Witch,realm=NA,application-id=3ErqAdtq,discussion-id=dq43G1Wc,comment-id=0000,timestamp=2015-06-07T09:54:02.867+0000)
You can count the CDR on their items and use third party site/addon to see if they're get any from masteries like you said. This seems like a quality-of-life change to benefit the less knowledgeable and hardcore players just like the jungle timers did. In other words, yes, beneficial and interesting.
Players can also use scaling CDR runes. With glyphs alone, this amounts to 15% CDR, which is highly impactful. Players can also potentially run more CDR, which can be dangerous early game.
Supposing we ignore third party sites, then this information is completely blind to players. Although it adds clarity to the game, it also removes the surprise factor. This is part of the bigger question of whether we should allow players to make more mistakes.
As an example, Starcraft Brood War was a very hard game because of its inconvenient mechanics, but also created separation between skilled players.