I would like to point out that this is only 5.3 so the raw numbers your using for total trials/dungeons are slightly misleading as 5.4 and 5.5 will both likely have more of each. Also, we have 6 trials or were you not counting Memoria because it only has the Extreme mode?

Yes, battle content has been trimmed. Yes, we have two races that feel unfinished. However, blaming the job reworks for it isn't likely the source.

Flying in 2.0 zones, greater community advertising tools like fellowships and the new FC recruitment tool, world visit and expanded cross world party tools, and all those QoL changes coming to almost everything in 5.4. Those all likely had a hand in it. Back end changes are rarely glamorous, structures for future systems take time, and maybe we just haven't seen the results.

What I'm saying is there are better theories on dungeon reduction than blaming the job tweaks.