I would just put some taller landscape (such as that cactus on the left) to fill in the blank wall space. There isn't much of anything green and growing in your photo. Maybe some palms?

I'd take care of the landscape first.

You need a contractor to give you some prices and suggestions.

Fabulous minimalist home. I'd remove the short columns with the light fixtures. They detract from the entrance door. I'd place large lighting fixtures on the wall on both sides of the door and down on the wall near the third large column. Remove rounded plants in front planter. Use wispy clumps of decorative grasses. Plant aloe or low clumps of decorative grasses along entrance walk. Remove shrubs in yard. Taller cactus or palms fronted by agave off to the right and left of house. It's not just a low box.

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Wow--great seguaro to the far left. Maybe a tweak to the landscape but I'd hate to see anything stuck on to "add interest" it's very attractive but it is what it is.

I do not think that having three doors in front is a good idea.

I would just paint the stucco trim around the windows, and change your landscaping. The landscaping will have the most impact with the least cost. You need lower plants so the windows aren't covered, and more variety for interest.

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House is nice. Take off the terra cotta tile and put on a zinc or metal roof, don't lengthen it, but change the shape of the overhang roof by squaring it off at the outside corners. rest is nice and will take care of itself. no need to add french doors.