I'm not opposed to the army men. I have a lego sized Minion that sits on top of my thermostat and chills there.

What about a small mirror, maybe diamond shaped or flip a square one somehow, to play off the diamond in the macrame? Also could see a small shelf with a plant that spills out and meanders down but I don't know if the plant would thrive near the register though. If a plant will be ok there you could also hang one from a macrame holder. Otherwise I'd go fun eclectic clock.

Try moving the macrame up 6 or 8 inches so that the dangling string clears the thermostate a bit more. If you made the macrame, you could add a slight gather at zig zag height that would also help clear the thermostat gracefully.

One pack of army men or pirates and one of dinosaurs would be my preference.

If open to moving it to a larger wall, it would be appreciated much more and look to make that area more fun.

so cool! i feel like the macrame needs a bigger wall to flaunt all of its awesomeness

I think I would just centre it on the wall a bit higher. I know it'll partially cover the vent but I think it'll let enough air through.

The wall hanging is too large for this space.

I am not a lover of boho but I do think the macrame is a nice piece that needs a better place to hang and I have no clue as to the rest of your home so I need pics of at least of the LR that I assume is decorated in the style you love, The feathers take away from the wall hanging and I have no idea about green army men , so maybe yes maybe no. IMO boho can go from awesome to racky in a heartbeat and green army men can do the same.

I agree that we need more photos. My first thought would be to paint the wall a dark color so that the macrame hanging pops but I'm not sure about that without seeing the rest of the space.

ONE idea please

The macrame is in the wrong spot. It looks like a second grate on the wall.: )

You're jamming a square peg into a NOT round hole. Even the paint on the wall doesn't make the most of it.

Be as boho as you like, but this is just not a wall begging for attention ....

Hang a "feather" and call it a day

The macrame is an exquisite piece and needs more space around it to truly show at its best.
Please consider finding a larger space for it and putting it against a contrasting background.
The feathery topping just muffles the airy nature of the woven piece and would be lovelier situated elsewhere and by itself.
Look for some artwork in a slightly smaller dimension to fill in the spots next to and above the air vent.
You can still incorporate climbing men into the spaces between the art.
I applaud any penchant for artistic decor,and like that you are making some eye catching vignettes.
Try to keep some airiness,so that each tableau vibes at its utmost level.

The macrame piece is so blah against the wall color you have now. Paint the wall a vibrant boho-inspired color to bring it to life.