Miguel, most of my work (Landscape Architecture) is as detailed as yours. Most of design teams I lead, whether as a subdivision planner, resort planner, site development planner, project manager,etc. require that I be able to provide road profiles and designs, storm water concepts, grading plans, etc. to the civil engineer. They, then refine my drawings under my direction to achieve the design goals. I believe Landmark is intended to be more than a planting plan generator. Unfortunately, it is the issue of which comes first - the chicken or the egg.
If you have developed tools which help along the civil engineering lines, I would market them to those of us who are patiently waiting for VW to fully realize that the egg needs to come first before others will buy the package. If they really thought of Landmark as only a landscape garden package, then we would already have a functioning irrigation design package.