Although I don’t have a disability, I prefer having my most common navigation not require key modifiers (e.g. cntrl, shift, command, …), and use the dominant mouse button. None of the presets currently provide this ease of use.
From a maintenance perspective, if you provided what @cageycruz suggested, i.e. a UI to define buttons and modifiers for each navigation action, everyone could define navigation to match their usage, and you wouldn’t be having to add whatever app presets come up.