There's several times when you can tell Lucy likes Natsu, in a romantic sense. This is one example...
Ch 425 p8
Ch 425 p9
Ch 425 p10
The proximity is an issue for Lucy, because she has feelings for him. This is some standard crush portrayal imo, but not shoujo level of course.
Plus I think Hiro lined all those ships up in ch 453 before the war. NaLu were together (and she was blushing again for some reason due to Natsu), there was a solid Gruvia moment, Erza with Wendy (but Jellal is mentioned), and there was that implication of GaLe due to those matching bedcovers.
I don't think anyone is denying that these major ships will happen... NaLu needs more than just fanservice moments right now though. The ST one from 425 is about as close to romantic as I can remember in recent times. The other major ships are just better developed at this point in the manga.
Crack ships are more my thing though, I just know it's all going down off-panel.
Can't get Juvia but might get Meldy??? How's that for luck