This change won't affect my family, but I can empathize with the families who are dismayed by it. I had small children from our first visit in 2008 to our most recent visit in 2015. In that time, we visited WDW at least once a year, sometimes more. Why? Because it was EASY. For us, it seemed like the whole system was set up to make it as easy as possible to travel with small children, and every time we started looking into other vacation spots, the ease of WDW kept pulling us back in (this is also the reason why, in 2015, we started vacationing in other places -- once our kids were older, convenience wasn't as strong a draw anymore).
Those who think it's no big deal because families, particularly those who have members needed EVCs, can just pay more and/or spend more time planning/organizing their trips, are missing the point a tiny bit. Of course they can, and many (most?) will. But by changing this policy and removing one service that makes a WDW trip easier for some families, Disney is losing one of the things that might draw people to WDW in the first place. I'm not saying Disney is utterly wrong for changing its policy or that there may not be perfectly valid reasons for the change, but however you slice it, the change makes a WDW vacation harder for some people. And when Disney makes vacationing harder, it gives folks one less reason to keep coming back.