As per #239 (comment) I think things like alt+arrow to jump words should be able to be turned off (or be off by default).
It does make sense for this stuff to be integrated into xterm.js so it works as most people would expect out of the box. However, in vscode for example, I would prefer if alt+arrow for example was routed to vscode's keybinding system so that users can define their own keybindings for this. In other words, I would like to turn this off and have vscode call into a public API to send the "Jump over word left/right" key sequence.