It's only on "old" content... I don't see the big problem.

The way people are talking about this echo buff, it sounds like you think it will apply to all content in the game.... When 2.2 comes out, everyone will quickly farm up full ilvl90 and try to beat T5. Most people will still not be able to beat T5 until at least 2 weeks, when the echo buff is added to Coil. Even then many won't make it.

When the majority of players finally beat T5 because of echo buff, the people that really want that extra challenge will already be well into doing the new 2.2 content, which will not have any echo.

As I see it, everyone gets what they want....

More hardcore players will quickly move on to 2.2 content, and because of how they are implementing the echo buff, they will get a "head-start" over the others.

The "medium-core" players (lol), will be able to quickly fill their gaps to ilvl90 (if they need it), and then get to try T5 for real, before the echo buff is there. Even if they don't make it, they get to try it out.... Then they can finally beat it with the echo buff.

The casual players, who don't want to have that level of difficulty, will get what they want, they will have a much easier time beating the content, which they will probably appreciate.... Also, the players that have progressed further, shouldn't even bother with the fact that everyone is beating that old content so easy now, because they are busy tackling Coil 2.0 or something, which they know these players won't get to do for some time.