Thanks for your personal observations of the C47 helm layout, I like to hear other peoples experiences ,thoughts on this subject as I own a Catana 471/2001model which is the model series 1997-2006 previous to the one you chartered.
I would like to address each point you brought up as it relates to my experience and that the two outboard helms are generally a major design feature of Catanas and some other brands.
"The autopilot and throttle controls were located on the starboard helm."
This is true of most dual helm boats unless the commissioning owners request controls on both helms from the factory(Rare) or are added subsequently(still rare). Autopilot controls on both helms are common, (I have them,love them, and are relatively easy to add as compared to throttle/shift linkages). Most charter spec'ed boats can differ greatly from owner/actively cruised versions in terms of level of equipment as you probably are aware.
"Side to" docking typically takes place on the stbd side, the engine controls are there and there is unparalleled sight lines as you probably can agree.
Docking on the port side is more challenging, I do it occasionly,carefully...,
but rarely find the need to.
"The chartplotter was inside the salon... having to run inside to check the chartplotter was less than ideal"
Totally agree! but as mentioned above, most owners add a chartplotter to the helm (relatively easy) and your charter company should have added one for the safety,comfort of their clients.
"From either helm you could only see from approximately zero degrees outward so anytime you navigated a narrow channel, passed another vessel, docked, etc you were completely blind for about a 120 degree arc on the opposite side."
This is a major stepback in the evolution of the new generation of Catanas.
I dont Know why Catana or Christophe Barreau the NA allowed this and the dealers/brokers that I talked to agree with me.
With my boat and model series there is good 360 degree (not perfect..) visibility from either helm as the area between the hard top and cabin bulkhead
was kept open for sightlines. I move from helm to helm for channels, other boats etc if more visibility is needed, hence Autopilot controls on both helms.
"I have sailed other layouts (like the Robertson & Caines, Lagoons, etc) that have a single helm elevated to where you can actually see where you're going, and those seem more skipper friendly."
I have not sailed the newest generations of those brands but chartered older ones and did not like the sightlines for sail trim, docking and general "being under sail fun" when I was forced to stay and steer under a hardtop, behind a cabin bulkhead. The helms were more often to the center of the boat, far enough away to prevent effectively assisting in docking or active sail trim.(looking thru a cutout in the hardtop/bimini top to check mainsail trim didnt work for me). But... that location was great for getting food,beers and mingling with cabin folk.
I have been aboard many of the new generations at the boatshows, many have certainly taken unique approaches to helm positions. Some have been executed well and addressed some of the helm position fundamentals but have certainly given up other important desirable fundamentals which I guess brings on the term "Compromise" or no perfect solution.
I cannot accept the logic of putting the mainsail/boom up so high to accomodate flybridge or mid bridge helms! You need a stepladder to reach the boom. (imagine when things go bad...)
I chose a Catana because its number 1 design prority was to sail well. This is reflected in every aspect of its design from helm positions,cockpit layout,dagger boards,carbon fibre rig,hull design etc. This is not true of many other Cat brands.
Please forgive the long winded reply, I would encourage you to take a look at Catanas of my series if a Cat is in your future.