I think Conan uses agile option, but his QU stat is much high, and remember you can use parry that can be interpreted as evade the attack and not only hit between weapons.
I say this because Conan sometimes use armor (usually a light chain mail, the old AT13) that doesn't penalize QU, or leather (AT9 or AT10) because the same (and it allows to use agile too).
So, IMO the AD for MA users mainly is to compensate that they can't use armor in any case, because DP cost and because some MA maneuvers limitation to carry weight.
But, if you want to use AD for anyone, then I see easy to allow kata for any style, and in this case you use the weapon table, but you can use only AD for weapons included in katas, look that this is not free as it increases the DP cost for that style.
Example: our style is for a group of weapons [5 points], let's say long blades, we add AD [4], and as we usually use the long blade, we add weapon kata for long blade [1]. Our style costs 10 points. Now we could add broadsword in kata too for 1 extra points, the style would be 11 points now. etc.etc. adding new weapons to be used with AD including it in kata.
See that if we want to use AD with 2 weapons combo, it is more expensive as it costs [3 points] for any pair.
It is possible for high lvl characters as I see more practical to add options than develop 2 ranks when ranks give us low bonus.
And Conan is a high lvl char