It's not becoming a standard norm, DPSing as a healer always has been a thing. Why put to waste Cleric Stance and the offensive abilities the game gives you? There's so much downtime from healing anyway so better DPS rather than standing there doing nothing and looking like an idiot.
It's not bad game design. Healers are there to keep your HP high up and remove detrimental effects whenever necessary. That's mainly their job and if they're good at it then they're healing fine, but do you really have to heal all the time when everyone in the party is in good shape or not in dangerously low health? No.
In my opinion, healers having the flexibility to DPS during fights is much better and fun than whatever game makes you spam heals 100% of the time. It's not like White Mages or other healers should be healing all the time in past FF games either, I mean I have my White Mage in my current FFT playthrough spam Holy all the time because it's so powerful.
I don't know what to think of you if you think spamming heals all the time when everyone is at full health and generating more enmity is fun and if you think DPSing as a healer is "bad" game design but to each their own.
