Originally Posted by
Noumenon
They settled on tomes due to looking at data for how many weapons were made by players in past relic content. Yoshi acknowledges though that: "However, there are some people who say that this reinforcement method is ``sloppy'', so it's difficult... Some people may dislike doing elaborate things like the old weapon enhancement content, while others may feel that the enhancement methods like this one are not enough. I think this is probably not compatible."
They settled on tomes as these days playing multiple jobs is much more common, and they think tomes being something that naturally accumulates as you play makes it best suit your individual playstyle.
The Manderville Relics have the highest completion rate of any relic so far. The more elaborate they make the relic content/grind, the fewer people make one.
There is an inherent conflict between people that "enjoy weapon enhancement as content" and people that "want a system that makes it easy to obtain weapons". Satisfying both is very hard.
They will take feedback into account for 7.x's relic series.