Your initial instincts with the gray striping seem solid from where I sit as does the brief comment by @Ellsworth-Hallett.

Consider the following:

a. The water feature does not fall flat. It is simply subtle.

b. It is on the terminus of an axis which gives it a position of strength based on location alone.

c. When it's operating it will be a more vibrant/dominant component.

d. Tiling it might create more detail than the space and water feature can actually support, visually speaking.

Live with it for a while. Post another photo while the feature is in operation. Looks like what you have in place is a winner without any tiling.

You need some plants. Flank it with Papyrus? Nothing that would block the view.

I don't see any water -- maybe the photo is take from too great a distance to show off the flowing water? Water movement and sound as well as the reflective nature of water make a fountain an attractive feature. Will it be possible to grow water lilies in it? Or float some colorful glass balls of different sizes? Lighting at night may be important for this fountain too. I think it has lots of possibilities, but the photos seem to show an empty box.

The fountain is fine. It's just lonely now, waiting for the rest of the garden.

I agree and some lighting at night to high light it , I would really get glass railing instead of the bars IMO they obstruct the view more than anything.

I personally love color and I think that having either tile, or painting the stucco, could make it amazing. But that all hinges on how the plantings, lighting, and other elements to come will play with it. Definitely a conversation to have with a landscape designer in your area.

If you visit a local tile store they will have many options including mosaic tiles which are common for many pool water features. If you decide to leave it then the stucco will look fine if you were to put in some exotic looking palms around it (might obstruct view). Otherwise mosaic tiles or nice concrete finishing would have been fine as well.

Some LED lighting in the water should help the look especially at night so you can see the water spillways light up. Example of how beautiful waterfeatures look with LED lights at night. https://www.youtube.com/watch?time_continue=367&v=hNhRTxsMjTU On the smaller pools on the ends you can probably put small bubblers with LEDs as well.

Thank you all for taking the time to comment. I think we are going to change out the feature strip...it just "reads" too much green. I'm thinking of blue mosaics but now have to decide where to stop and start the new tile. We are also considering adding a planter on top. I'm attaching new photos of the water feature, proposed planter on top, lighting. Question: would you tile the whole center section that has the 3 sheer descents in the blue mosaic? Thanks everyone for your input!!!

What is your water quality? If your water has lots of minerals in it, that will leave white residue on the blue tile which may disappoint you. Proceed carefully. If it were me ( and it's not!) I'd go with mango orange stucco and green big leaf plants around it. But I'm a tropical nut.

Very nice solution! The texture and subtle colors are perfect.