It started in stormblood.
And in heavensward that was 1 healer 3 dps (no tank) yet nobody complained about it.
They don't want to make dungeons hard. So you don't need healer, or tank either.
As long there is no hard hitting tank buster you can even do it with 4 dps if they know what trey are doing.
Keep in mind there is people who struggle doing dungeons even with a normal team, wiping on simple pack or bosses, and they have to cater to them.
Thanks for the faster queue for my healer btw. (I doubt it gonna do anything except the usual shortage of tank/healer because of new dps, usual)