I personally enjoy leaving works very open to the viewer's interpretation. I work at this. I contend it's very hard to do this. It is very easy on the other hand, to make a specific intent or evoke certain responses; i.e. bloody war scenes or Van Gogh's Potatoe Eater's depression. I prefer the challenge of the former where one work can honestly illicit numerous responses.
I further think being too vague in meaning has no power as in many of Parrish's lounging youths along classic pillars. It's a delicate line one must try to walk. The reality is that most works fail in the phase when the idea goes to canvas. I think many overly poetic works have the power of fishbowl [feedback].
As to poetry in paintings; some have far more than others by design (intention) or by default (inability of the painter). There are masterpieces which are strong and shocking but not truly poetic. My favorite works have power, meaning and poetry. These are rare.