The 75/25 healing/dps ratio sounds nice, however there is many ways to look at healing downtime. One way is the concept of what I've been calling "mistake space"; time spent DPSing in optimal scenarios is time that could be spent healing mistakes made by the healer or their allies, thus "mistake space".

The suggested ratio may be way too punishing for casual players who need more healing generally. Whether it is bad cooldown usage or just standing in bad, if a healer only gets 1 gcd out of 4 to fix mistakes, then they can easily run out of mistake space. Not to mention combat rez; in it's current form it'll only be useful if you will be aoe healing as a matter of course. And if the healer doesn't heal perfectly, then they may end up giving tanks and dps to play perfectly since the healer uses up all the mistake space for themselves.

I think this is something that the dev team is trying to avoid.