I would argue that, despite the beautiful imagery in the balcony scene, it isn't a romantic story at all. In the chorus to Act II says this:
Now Romeo is beloved and loves again,
Alike betwitched by the charm of looks
Shakespeare is pointing out the foolish behavior of the young lovers. He is showing that Romeo is carried away by appearances. Before the balcony scene even starts, Shakespeare cuts the "love" off at the knees with this disclaimer.
Instead of a romantic tragedy, it is a tragedy of human impatience. All the characters suffer from hasty action - Tybalt, Mercutio, Romeo, Juliet. It is the hasty decision of Capulet that pushes the action forward in Act IV.
I have trouble with the term romantic tragedy, in that the ending destroys it for me. I find the plotting of Romeo to join Juliet too much. Of course, I do not possess a romantic soul. I would think that for him to have taken immediate action if he were so inclined to kill himself makes more sense, than taking a trip in search of something to do the job.
I always think that in that time, a little reason would have crept into Romeo's head.
You see that the plot of drama is about love.Can we say that it is the romantic tragedy?
Is it THE romantic tragedy? As in, the only one, or the main one? Maybe. It is certain A romantic tragedy.
In many tragedies, the final sad ending comes from the actions and qualities of the single main character (Hamlet) or of a hero and those opposing him (Lear). In this one, though, the tragedy is mutual, and depends on the romance as action, so yes, it is a romantic tragedy.
Othello is too, in its way, but it is not as balanced.