Martinus, it sounds like you’re suggesting that the keybinds in a syntax-specific keymap should automatically be restricted to that syntax. This could make sense in simple cases, but there are complications that would make such a feature narrower than it might seem.
First, a keymap or other configuration file is not necessarily associated with a particular syntax. A given keymap may contain bindings that pertain to a single syntax, to multiple related syntaxes, to multiple unrelated syntaxes, or to no syntax in particular. For example, my User keymap contains syntax-specific bindings for Markdown, CFML, Oracle, JavaScript, and more, as well as general bindings that apply to all files. Or a JavaScript-specific keymap may also contain binds that apply to JSON files. There is no sensible default in many common cases.
Second, there is no way to specify a syntax generally for a keymap file. The structure of that file is simply an array of bindings, and adding an explicit keymap-wide syntax would complicate that structure. Deriving the syntax from the file’s name or location could be problematic as well, not to mention potentially surprising.
Third, even if a given set of keybinds pertained to a single syntax, and the keymap file had some way to indicate that unambiguously, it is common for some bindings to be even more specific, applying only in a certain subscope. You would still need to manually specify a context in such cases.
Fourth, any kind of implicit restriction on keymap bindings could make it more difficult to create and customize bindings. Right now, if a binding is restricted to a particular syntax or scope, that is explicitly specified in the binding. This makes it easy to understand in what circumstances the binding will apply, even if you’re not familiar with that particular keymap file. It also makes it easy to override the default behavior. If bindings in a keymap file were implicitly restricted to a single syntax, and you wanted to broaden or narrow the scope of a binding, then you would have to either remove that binding from the file and put it in a new keymap or change the implicit syntax restriction for the entire file and possibly change all of the other bindings as well.
I understand that you find the current syntax to be overly verbose, but I hope that you can understand that the current system attempts to strike a balance between power and simplicity. Adding implicit syntax restrictions might make some simple cases simpler, but it could make a lot of cases more complicated without adding power. Therefore, I don’t think that the developers are likely to add such restrictions.
If you often find yourself editing keymaps, I recommend the PackageDev package, which adds better syntax highlighting and completions to keymap files.