One of the annoyance of working with higher-order signals (i.e. signals carrying signals or events) is that the eq parameter has to be specified explicitly in the combinators that carry these values with ( == ), otherwise update steps will fail now and then with a hard to track down:

 Exception: Invalid_argument "equal: functional value".

We could provide two module Se, Ss that specialize the combinators for signals and events using S.Make. But this is similar to have to write eq:( == ) you need to remember you need to use this alternate set of combinators for such signals and this puts an unwanted burden on the programmer.

I'm not sure something can be done (well implicits, I'm not sure I like the idea of implicits but in that case that would solve it). The problem is that interesting FRP programs are higher-order.