Let's try to diagnose why production has been poor first.

Is the trellis in full sun? Does it get at least 8 hours a day of direct sunlight?

Did you add some sort of fertilizer to the soil? One of the hardest things about growing in a new garden, particularly if growing organically, is getting the soil composition and nutrients right. The soil has to have good microbial life existing there in the soil that will digest the organic fertilizers and convert them to nutrients that the plants can take up and use, or nothing will grow well no matter how much organic fertilizer you add to that area. If you've added a substantial amount of compost or composted manure to the soil, your microbial life should be adequate, but if you haven't, it may be the microbial life that is lacking. I like to add half-rotted wood to the soil to stimulate biological life in the soil, or leaf mold stolen from our woodland, or spoiled hay that is 3 or 4 years old and already practically compost. You often can stimulate biological activity in the soil by using dry molasses or a liquid molasses tea drench. When a new organic gardener is having issues with the soil failing to produce a good crop even though the crops seem to grow well, the issue often is that the soil isn't amended enough yet to have good microbial activity and the nutrients aren't making it to the plants.

I plant pole beans every year on one of three cattle panels. Every year they do fantastic.....until last year. The plants grew fine, but production was super low at a time when it would normally be hard to keep up with the harvest. Then in the Fall it started to produce and act normal, but didn't have a lot of time left with good temps. It certainly wasn't lack of rain as we had 67 inches last year. I know my soil was good and 4 feet from them I was growing cucumbers that produced all we could eat, give to neighbors, and 72 pints of pickles. Some years it is just hard to understand what happens. Dawn is a lot more scientific than I am, so maybe she can help you diagnose the problem.

This particular part of the garden is most fertile. Cabbages beets onions tomatoes all do really well in this section of the 8000 Sq ft garden. Full sun all day running east west. Fluffy soil with worms and nice rich brown tone. I thought it might just be legumes that have a problem here. I could plant some cucumbers or other Vining squash and see what happens I guess.

Maybe it was too fertile for legumes? I let legumes grow in good soil, but not in heavily enriched soil that has a lot of nitrogen because that just gets you tons of leaves and not many blooms/beans.

I'd try cucumbers there and see how they do, or you could grow cantaloupes, muskmelons or icebox melons. I grow them all on trellises. However, cucumbers would give you the quickest and highest yield for the space.

If you want to grow something there to sell at market, it might be a great spot to plant ornamental gourds for the fall market weekends.