Vim: Plugins should provide "named" key sequences to customize hotkeys, not variables

Many Vim plugins use variables to allow users to customize hotkeys to do some features. For example, users have to write let g:plugin_feature_hotkey = '<F2>' or something like this into their vimrc to customize the hotkey to do a feature of a plugin.

But this method has the following problems:

• Only 1 hotkey can be assigned to a feature. Sometimes it's necessary to assign 2 or more keys to the same feature, but this method doesn't provide a clear way to do such customization.
• Modes in which a specified key is defined are unclear. Some plugins define key mappings in unnecessary modes. If so, it causes some problems but users cannot avoid them.
• Some plugins add a prefix to a value of g:plugin_feature_hotkey and use the resulted key sequence as the hotkey. In this case, users cannot assign any key sequences to hotkeys.

The better way to customize hotkeys is: (1) plugins provide a "named" key sequence for each feature like <Plug>(plugin-feature); (2) users use :map and other commands to map any key sequences to the "named" key sequence.

This method doesn't have the above problems, and it has the following merit for authors of plugins:

• Some plugins provide the default hotkeys for each feature. With "named" key sequences, the definition of the default hotkeys becomes easy and readable. For example:

  " Named key sequences
  nnoremap <silent> <Plug>(fakeclip-p)
  \ :<C-u>call fakeclip#put('', 'p')<Return>
  nnoremap <silent> <Plug>(fakeclip-Y)
  \ :<C-u>call fakeclip#yank_Y()<Return>
  ...
  
  " Default hotkeys
  nmap "*p  <Plug>(fakeclip-p)
  nmap "*Y  <Plug>(fakeclip-Y)
  nmap "*yy  <Plug>(fakeclip-Y)
  ...

  and users can use the named key sequences for their customization as follows:

  " Like the one of MS-Windows
  nmap <C-v>  <Plug>(fakeclip-p)

  (the above examples are excerpted from fakeclip)

So that every plugin should provide "named" key sequences like <Plug>(plugin-feature) to customzie hotkeys, not variables like g:plugin_feature_hotkey.