I don't understand how you can take the position that you can't affect movement on one side of the board from the opposite side. That's just ignoring some of the basic principles of the game. It doesn't matter if you're playing gunboat or full press, but if Turkey opens to Armenia or England opens to the Channel, its going to effect play elsewhere.
To a certain extent, Octavious, you're right about S1901. You're opening with no information about the rest of the board. You can take this a few different ways. First, its an opportunity to set the tone for the entire board, or at least among your immediate neighbors, with a high risk, high reward opening. This could backfire, obviously (England bouncing in ENG plus a Russian northern opening, for example) but it could also pay off big time (Bohemian Crusher plus a Turkey anti-Russia opening). You can also force other players to respond to your play, rather than the other way around. It can sometimes mean the difference between dictating play and playing in response to other moves.
Of course, gunboat often rewards conservative play, which is why most high level games will have the same typical openings - for example, France A Bre-MAO, A Par-Bur, A Mar s A Par-Bur. But this just puts that much more importance on F1901. Germany often has some big decisions in F1901 - a possible bounce in Sweden, protect Munich, offer support to Belgium, take Belgium for yourself, sneak behind French lines, plus a few others.
In short, its silly to call gunboat "limiting"