In my view, it is to some extent at least, about labels.
Labels which, over time, have collected all kinds of collateral baggage and in a lot of cases no longer represent that branch of art they once so accurately described.
Even the OSD has trouble defining 'Romantic' but the word that occurs most throughout it many related definitions is, 'imagination.'
So I guess that doesn't help us a lot either.

For a lot of people, 'romanticism' conjures up images of languid young men with lacy cuffs reposing beside a stream, smelling flowers. I don't think Robbie Burns would appreciate that very much.

Perhaps the most effective way to define romanticsm is to compare this kind of work with modernism. But I'm not about to do that. Modernism (and post-modernism) is a genre of poetry that I do not pretend to fully appreciate and so do not feel qualified to make comparisons.

If pushed, I would define romanticsm as that branch of poetry that relies heavily on subtle images and on beauty of language/expression, rather than on intellectual comment and metaphor. I suspect that comment will draw a bit of flak as well.

The same modernistic thread runs through music, sculpture and art itself. Some abhor it, some are bewildered by it and still others embrace it completely.

I read a quote some time ago (I forget the author) who, during a discussion about why poetry is no longer popular and why it (poetry) doesn't sell, said, "People ignore poetry because poets ignore people."

cheers
Peter E