Titan HM wasn't why the direction of the relic changed. What happened was that players wanted their already obtained relic(s) to undergo stages like with XI, where it'd gradually grow more powerful over time by doing different tasks. So basically, a continuation of the Relic Reborn concept. Since it wasnt SE's intent to continue the storyline past that quest in the first place, they fell to their standard practice: devising ways to get players into doing older/neglected content under the guise of the Zodiac Braves storyline.

Same way with the original Hunts. It wasn't in their plans to add it, but they shoehorned it in due to fan request, hence why it was such a mess first time around (e.g. the Naul fiasco)