Now when I think about it, I tend to play the 80 lvl content with my 2 healers, WHM and SCH, the most, despite having SMN leveled up, for example.

I haven't actually thought about doing this like you said. It seems to be the best approach- having the best gear on the class I currently enjoy the most at lvl 80, and not on the class I've just leveled up to 80.

Thank you for you replies. I'll go now and spend the tomestones on my healer and leave my would-be 80 lvl Bard with ilvl 450 gear in the future.

P.S. Yeah, if there will be no new tomestones until 5.2 and again another ones until 5.4(I assume?), then I see no reason in hoarding them.

By the way, do you happen to know what exactly ilvl will the new gear from the NieR alliance raid have? Will it be the same as the Phantasmagoria one?