Can’t say I’ve ever had any problem with a landscape architect as far as their work goes. However I was in a networking group with one and he was referring to himself an architect versus a landscape architect, and that rubbed me the wrong way.
I’ve worked with a lot of Landscape Architects and the ones that I feel are most successful are the ones who try to compliment the overall vision of the specific project instead of just doing a boiler plate design they use on every job. I also really appreciate it when they bring ideas to the table.
Biggest negatives with Landscape Architects would be the same with any of the consultant team, lack of communication, missing deadlines, incomplete or incorrect information.