There are some canvases that would be ruined visually by the use of textured stitches and "fancy" threads, but that do need a bit of subtle enhancement.
I bought this gorgeous piece about ten years ago at a trunk show by MINDY, one of my most favorite of designers - I have three of them, and have not given myself the pleasure of stitching them, as they are termed "personal" stitching for me, and other things have had to come first. Now I have found a purpose and can justify the time, and am thrilled to be able to go ahead and start.
As I have used my stash threads diligently in the last year, I am almost out of silks, and have decided instead of pricey "refills," I will use DMC cotton floss with a bit of perle cotton here and there for emphasis. The beads are the kind that don't sparkle, but just add a bit of texture and gleam in a subtle way (Sundance, of course) I think many would be tempted to use the squares as a patchwork sampler of decorative stitches, which would destroy the visual impact of the beautiful art nouveau flower.
I'll get on this project tomorrow, hopefully, and can make posts of progress as I go. If you aren't familiar with Mindy's work, do go see her HERE - her shop and web page are fabulous. The canvases are stitch painted, and quite sophisticated in the areas I like - the Asian and Art Nouveau. Her colors are superb!