Thanks for weighing in with a differing take on this issue. I agree that being able to see a plotter from the helm is of great benefit: improves safety. I also agree completely about having access to being able to see a radar display from the helm: mine is visible from the helm and is under the dodger. I also suspect that luck played little role in your having an ECDIS course under your belt: rather good judgment on your part in choosing the course in preparation for your cruising.
I do disagree with seeing the plotter at the helm as the same as a plotter under the dodger. I will elaborate my reasons for thinking the chart plotter at the helm is not the wisest location on an offshore sailboat (and actually, to a lesser extent, on any sailboat).
Neither Phillip nor I are against being able to see the chart plotter from the helm: quite the opposite. I can see mine under the dodger quite easily accomplishing all the visual cues that you so correctly value in your post. Phillip also mentions his being visible by those in the cockpit. So, if one can see the chart plotter under the dodger from the helm, the only reason to have it at the helm is to do navigation and plotting: to work its controls. Possibly there are really big boats where helm position is too far a distance to see a plotter under the dodger, but I have seen this accomplished on boats in the mid 50s in length.
For most far-ranging boats, the helm is rarely manned. The vast majority of our mileage is accomplished with no one at the helm. I believe this to be the case for most passage makers and even, most coastal cruisers. An under dodger chart plotter is much easier to monitor and manipulate from one’s usually watch position sitting in the protection of the dodger.
Anyone at the helm actively driving the boat should never have interference with his/her situational awareness, most of which should be directed outside the boat with occasional glances at the chart plotter. Doing any navigation plotting interferes dramatically with situational awareness. This is fine in open water with no obstacles about, but active adjustments and navigation decisions are often made when entering a harbor, transiting a passage or in the vicinity of obstacles. Think, perhaps, of the danger inherent in handheld cell phone manipulation while driving.
Lastly, instrument manufacturers have come a good way towards making equipment truly waterproof, but having such an important piece of kit and its many electrical and data exchange connections exposed to rain/sun etc. and to the assaults of salt water and seas when offshore seems to be asking for trouble somewhere down the line. Then there is the ease with which it might be stolen, something I think about even in the more hidden area under the dodger where my plotter lives.
So, in the end, I see no advantage to a helm position plotter and lots of potential disadvantages.
My best, Dick Stevenson, s/v Alchemy