Power dividers and directional couplers might be wise to extend to fibre-optic devices if going for FA. Hard to argue against as the article now covers waveguide and fibre is a form of waveguide. Now also a comment on the talk page about integrated photonics.
The opening of Morse code history section has a couple of problems. There is a false comparison between Morse beginning development and Cook and Wheatstone putting into service. Cook and Wheatstone were in fact first. Also, much of the Cook and Wheatstone part is a bit of a diversion from the article subject
system equivalence needs a makeover, and analogical models (also in need of a makeover) should either be clearly differentiated in scope or else the two should be merged. Some material from mechanical-electrical analogies could usefully be transferred. Also, the redlinks effort variable and flow variable should link to somewhere useful. Actually, flow variable is not a redlink, but even worse, it goes somewhere irrelevant to analogies.
admittance needs the ungenarization reversed, or else individual articles created
short circuit and open circuit. We really should have a network analysis description of this. Create redirect from short circuit (circuit theory) and open circuit (circuit theory) (or appropriate the current disambiguation page at open circuit)