Ultimate is not just for hardcore raiders, it's for any raiders who wants the extra challenge to see how far they can go even if they can't clear it. Don't have to be now, can be later in patch 3.3 where they overgeared and went back for the mechanics. The number of players who attempted raids and showed interest in UltiBa, from what I observe, is quite substantial and to neglect them means losing valuable customers and as some pointed out, some of the most valuable sources of game info we ever have.

The Final Fantasy XIV dev team is split into multiple groups, each responsible for different areas of the games like raids, dungeons, lores, graphic etc. Having the raid team design UltiBa doesn't mean the other teams stopped functioning, especially when they are re-using assets, as such will not have an impact on content turn out.