I never leveled off the vault but yesterday I did enter one something that was close. (I think?) we had a newish tank and 2 dps (one was at level while the other didn't do any job quests past 50) So there was one group where I was talking to say something when monsters where nearly dead, thought I had enough room to talk (that the group would die before anyone else) and sure enough the tank died and .. yeah.. stopped talking and healed till the monsters finish off dieing (so yeah i know it was my fault but I am honestly not used to DPS that low, and yes I did make that comment in the pt)
The final boss was ruff as heck O_o I had mp problems and I ended up soloing 3 of those fire orbs at the second attempt. The first wipe was from people taking too much damage and I just ran out of stacks to heal it all up. Again at the end of second attempt I was out of mp, and nearly wipe again over it....
I do not think it is a good idea to have situations (i/e make things more healer demanding) since that means 3 others need to be on top of the game more. Tank under geared? you wipe, over and over, dps do not do enough damage? you run out of mp over and over. So you need to look at what this game appeals to and that is what the forums call "lowest common denominator" If you want to make things more healing intensive, the content will be too hard for large amount of the playerbase, so there needs to be something else.
In the end though, removing/lessin healer DPS or making fights more heal intensive would most likely drive more people to quit then it brings in, so this not really a solution.
So to those that say SE never intended healers to DPS in group content because it was not a factor in calculations is a BS argument. They did a baseline to allow wiggle room since people are not robots. If they factored in healing DPS, it would be too hard and people will not be able to do the content.
Too much mp/cast time, just heal over to allow dps more.