The planting plan here is typical of many designers and I speculate that most, or at least many other designers, would not "have a problem" with it. It is me, the contrarian, that objects to some of its features. I suppose that many designers would object to my objections. In the end, it is you who has to make the call as to what is acceptable, or not. I've merely given you some ideas about what would bother me. I don't know what your arrangement with the designer was, but it seems that you are at the end of the design process with a finished plan. Wasn't there a concept plan or schemes presented before this that would have let you know the direction the plan was going, and where you could give input before it was finalized? Most designers don't like to get all the way to the end and then be asked to make a bunch of changes which should have been known about at an earlier stage. If this is the first iteration of a plan you've had to respond to, then it is what it is.

I think the patio concept and shape is nice. The only issue I'd have is how close it is to the house, and that its closeness squeezes the planting bed (where you have hibiscus) seemingly tight. I don't have any way to measure it, but it looks tight. We can't see the back wall of your house, but if it's typical, I'd want the bed to be 6' depth.

It will not be sufficient to tell the designer to "create a low maintenance landscape," as the answer you'll get back is that it already is. You'll need to specify that the centers of foundation shrubs are planted X distance from the foundation wall. (For me it would typically be 3 1/2' to 4'. But it depends on nearby hardscape features and the bed size. Sometimes those require planting standards to be adjusted. If bringing the shrub centerline farther from the foundation wall means that the shrubs will be too close to a walk, then the shrub centerline and bed centerline should match. Moving shrubs farther from the house will squeeze plants you have in front of them. You may need fewer of the front plants, or to do some rearranging.

I'd want the redbud to be not closer than 7' from a line representing extensions of the planes of the side and front house walls. This would likely have the tree be diagonally placed off of the house corner, as I showed earlier. The bed would then conform around the new tree location.

Be sure the "cherry laurels" used are shrubs, not trees.

If you get the trees and shrubs placed far enough from the house, then I wouldn't worry much about the smaller plants, as they can be adjusted later as part of ongoing maintenance.

When hiring a designer, it's best to hire one whose work you've seen and think highly of in all ways. Then you only need to be concerned that the basic concept is sympatico with your goals. You don't need to worry about the standards or little things, except as much as you have knowledge about and take interest in those things.