Ignoring? Not really as they clearly reused numerous assets including unused assets resting in XIV 1.x's data for up to 3 years, which means the engine development aside, they still managed to create 3 new entities:
Arcanist's New form (it originally was a staff user that had potent buffs and used traps.)
Scholar
Summoner
Now - We know that Summoner, as I said, is basically a DoT DPS with a vanity pet since let's be honest, most of your damage comes from the Summoner itself. Scholar is a healer with 2 pixies. Now, "completely ignoring" would be what SE did when they completely ignored Musketeer that's been waiting there for 3 years. What prevented them from finally finishing that class/job but had the resources to retoool Arcanist along with adding two brand new jobs..? No, I didn't ignore anything.
The only thing I remember is them saying Arcanist wouldn't be ready for public testing but will be ready for launch.We were very lucky in that we managed to even get Arcanist on release which (if you recall) was quite a pressured situation for them to get it ready, finalised and done for launch.
Something something Arcanist something Scholar something Summoner...I'm not saying they couldn't have made time, but there were most definitely other priories to sort out beside adding in new jobs/classes.
Actually...In XIV 1.0 development interviews they stated they could pump out assets a lot easier in XIV than they could with XI including a deformer to easily and quickly create armors for the races which dramatically cut down production time. Iirc, over on XI forum they stated it takes about the same time to create assets for that game as it does this game. Asset creation is usually dependent on the engine itself which by common sense, you'd think it'd be MUCH more easier to create assets for ARR than XI since even Yoshi said recently they literally had zero issues working with the PS3 or PS4 which means there's really no "barriers" that would make the assets difficult - Hell, it's more streamlined than ever these days compared to when XI was developed.Another point would be that asset creation in FFXI was a much simpler process