Which makes perfect sense.
Otherwise you'd get a repeat of what happened back in Patch 2.3 and Ramuh EX (as in, you could totally let Titan-Egi tank him).
Now that's both, harsh and unfair.
What about the other jobs that used to rely on elemental resistances/weaknesses in other games (such as WHM or BLM), then?
Should they delete them as well?
Personally, I think they did a pretty good job at making all classes/jobs as balanced as possible, so they're all viable (unlike in FF11, which was a mess).
Also, it's still too early to tell on them "not fixing and learning from mistakes" when 6.0 is just around the corner.
So let's wait and see what they come up with by then, shall we?