Remote design is possible, and it's something we do occasionally. But everything else being equal, you'll get a better and more nuanced design from the pro who can actually visit the site.

Many LAs visit sites in multiple states.

I've done projects in several states but the ones where I have not visited the site personally (Alaska) I was less engaged with and even with copious photos the project was hard to envision well. Designing from a remote location is not ever going to be my first choice and like Rev, I believe you get a much better end product with onsite visits and in-person client interaction.

I've found that that if unable to visit the site, a major factor becomes pictures and how well they convey the site. Anyone who peruses this forum much discovers that most people asking for help post a picture, or pictures, that are incomplete and sometimes almost worthless. They rarely show complete scenes from end to end, including surroundings. Depending on the scope of the project, it could take many views, each comprised of many pictures, in order to gain a good understanding of the site. Another potential 'bug in the works' is existing foliage or other clutter that obscures views of the site. In some cases it could be impossible to take good pictures until a clean-up of the site is done. If the site is clean and pictures are comprehensive, and if the scope of work is not too demanding (such as planting only), then it would not be too difficult to do. If grading was involved, the work would require a topographical survey to be performed ... producing the same information an LA would have if they were local.