By improved I mean new cultivars, perhaps for beauty, color, disease resistance, etc...
My suggestions are mostly for color and size.
Take Plantain and Dandelions.
I would like to see giant dandelions with large yellow or orange flowers, they are pretty in spring but the small size is a downfall getting lost among tall grass, and flowers don't last long.
Plantain leaves when cared for get quite large, the flowers on stalks are inconspicuous, but if you look closely they are pink or white. Now imagine flower stalks the thickness of sausages and flowers as large as US quarters or silver dollars in pink and white, among the large leaves as big as hosta leaves, that's a Plantain Id love seeing in my garden!
In general for any flower, variegated leaves with variegated flowers all on one plant. Some flowers I think exist like this, but not many.
More hosta flower colors than purple or white, and red leaves hosta.
