It is not harder to move with mouse/kb over controller...but it takes a little practice. Titan would NOT be a good place to practice this. Ifrit Easy mode however would (for example). As would AK.

Although really, until 24-man content is the in thing, you should be fine healing with game pad if it's what you're use to...

I'm not going to get into the kb+m vs gamepad debate as i think good players can be on both.

I will say this, I played all of 1.0 as a Healer-primary and used gamepad. No one ever complained that I was 'slow' or 'wrong'.

But, this game, healing with a pad annoyed me, esp open-world content like FATES. So I purposefully switched from my old reliable gamepad setup to a gaming kb+mouse setup...I love it. And find it way faster/easier. But that is me. And it DID take practice.