For the one who says that the Development of the NatsuxLissana is real or better than that of the NatsuxLucy I think that it should bring authentic examples shown in the manga outside that it disgusts or not a couple.
Why not be like this only one Hater of a couple and fanboy of the other.
The NaLi only had a Omake of "Development" and was not even the important one, it was Happy, although in the anime they wanted to look more, I think it was to see how many were swallowing the story of making a Shp War.
If the reason to say that it is wrong for the Ecchi, I think then better see another manga, the Ecchi in the Shounen is partly a way to put some more relationship between the characters, but only see Akamatsu where the characters with More Ecchi scenes are the ones that end up together.
Just look at the scenes of each pair and we will see that the development of the NaLu is much higher than the NaLis, even in the Fairy Tail Magazine, in the chips of Natsu and Happy clearly sees the importance of Lucy for them, much greater than the That Lissana may have
And I clarify, Lissana I like, but equally, that try to justify it with that because ... it is laughable.
An extra thing.
The one that some like the Ships do not do the Manga Cancer, or the Ships by themselves are not cancer, the couple relationships Humanize to the characters, they make to feel that they really are alive beings and not unidimensional personages, the wanting to blame of a Taste as you see a series is very unethical, because after all, it is only part of the Fandom, it does not affect how it is handled in the official plot to yes that I think generalize this Wrong.
In the end everything will always be a matter of likes, I could create in a theme ALL the reasons why MYSELF I see the couple with pleasure and could find a thousand blind spots to the others.
But we know that this is a matter of Fans, we do not know in the end how the Author will do.
Even if it bothers me to say that one has more development than the other without real evidence more than the typical ones of "I dislike myself for this and for it I do not think it should be given"
Remember that Mashima left us the possibility, either with NaLu, GruVia, GajeVy and JeRza.
There are as many clues as couples could give that really are few characters that could intrude without it being rare or illogical.