As long as the next step doesn't require a large amount of lore, I think the existing grind is okay.
The entire process is relatively cohesive.
You get GC seals from the fate grind step and from the gear-turn ins in the dungeon grind step. You can use those seals to purchase the i210 turn-in items or convert it to gil to spend on sands (or if the conversion rate is bad, you can just trade for moonstones straight up).
You get 4 UI items per day from Beast Tribes. The poetics can be used to purchase sands or UI items.
You get 1 Aether Oil per week from the weekly CT quest. The poetics can be used to purchase sands or UI items.
You get 17 Singing Clusters per week from repeatable quests.
And because the rest of the relic doesn't really require lore, you can spend all your lore on Umbrites.
That way, assuming you just do your dailies and weeklies, you get one up-to-date relic every 5 weeks (bottle-necked by the Aether Oils mainly) with no other grinding.
Currently I have 3 (and almost 4) up-to-date relics and 2 more at i210. Outside of the my first relic, I really haven't went out of my way to grind anything. I just did my normal daily routine that takes maybe an hour or two.
So yea... as long as the next step isn't a lore grind, I think the existing quest cycle is fine. The only thing I think needs changing is the singing cluster quests need to be made available regardless of your relic progression. That way, while slowly accumulating Aether Oils with the CT weekly, you can work on your i240 progress by spending lore on umbrites and can work on your i260 progress by doing your singing cluster repeatable quests. While this doesn't matter to people who've already done one relic, it'd help streamline the grind for first time relic questers.
If they do add another lore grind, though... well, I would be really disappointed at the complete lack of creativity. This entire relic has been copy-and-paste but it'd just be another slap to the face. But yea, they'd probably need to adjust how we get Umbrites then.
I think the i270 and i275 relic steps should focus much more on how to keep your players active given the upcoming content lull before 4.0. Lore grinds don't actually do that well since it just forces players into whatever is the most efficient means of grinding lore and kills everything else.