I mean, it was mentioned that he was:
1) Weakened due to the destruction of the seeds (to the point of Natsu going from not being able to land a hit to actually keeping up with him)
2)
Weakened due to not being fully awake yet
The story heavily implies that Aldoron was far from his actual peak, and the fact that he had 2 separate huge nerfs kind of confirms it.
Look at it this way as well: Ignia Natsu beat a 50% Mercphobia, and as the result, his hands got burnt to the bone. And yet when Natsu used his own DF, his hands were alright, implying that there is a big difference between these forms.
So far, it seems like:
DF Natsu = not fully awake Weakened Aldoron < Weakened Aldoron <> 50% Mercphobia <= Ignia Natsu < 100% Dragon Gods
Currently, DF Natsu is still not quite on the level of full-powered Dragon Gods (Which is a good thing, because what's the point of him progressing to their level if he is already at it then?)
Personally, I think that we should scale DF Natsu to the Giant Gajeel's feat.