Berserk should have the romance tag. It has more romance than most of the series tagged here but the 2/3rds of the series is Guts being romantically motivated.

No, it shouldn´t. Event the first anime or the film trilogy that only cover the Golden Age portion, which go for that subplot the hardest, aren´t deserving of romance as a leading genre. The manga is also tagged with Romantic Subplot (96,9). Says it all I think. The genres are fine as is.

I also read EU/US comics and am a librarian.
Manga-Masters, My ANN-Lists + Imdb