Roguey, role-playing isn't defined by story or by deciding which branch of the story-state you wish to interact with. If this was the case then
any video game would be considered an RPG. It is ironic that the words you use, "scripted and systemic reactions to...", are exactly what Wizardry has the most of!
Trapped-chest scenario, class and race interaction, party and character advancement systems, non-linear itemization which is tied to game-world areas instead of being tied to specific monsters, plus an explicit focus on navigation of the game world (exploration) and, lastly and most importantly, a direct focusing of subtle resource management inherent to the D&D roots from which these games come from: these are basically the essential ingredients in the Wiz-formula, and, (not to overuse the word)
ironically these are elements that are usually lacking the games that
you consider to be RPGs.
There are many ways to point out elements from which the RPG "template" is drawn, and the Codex itself was founded on the intent of making threads about it all the way back in 2003.
I can assure you, though, that anyone who doesn't think the Wiz-blueprint does not contain a full measure of the RPG template simply isn't being objective enough, or to be more generous, simply isn't informed enough about RPG system design.
TL;DR: Choose-your-own-adventure type of RPGs existed long before branching dialog trees, and, as a matter of fact: these elements are not even native to the type of A/B/C story-state RPG you espouse.
The myriad of system interactions that come into play when a party is making all of the decisions regarding whether or not to inspect if a chest is trapped and then decide whether or not it is worth risk/reward ratio of disarming it and then, lastly, having to choose whether or not to return to town to identify the unknown item or to continue onwards contains more
role-playing than any RPG where the only examples of systemic role-playing consists of A/B/C story-states.
Why? Because all of the possible outcomes and decisions involved in the trapped-chest scenario are drawn straight from the game's gameplay systems and are engineered to dovetail with the player's psychological approach to their exploration. Is it the most complex mesh of systems ever? Absolutely not, but it is still to this day, one of the simplest and most elegant exampls of emergent RPG design and gameplay one can utilize to showcase RPG game design.
And it consists entirely around player-driven choices which are based off the game's symbiotic game mechanics, and
not around pure player fancy.
The type of RPG design favored by people who dismiss Wizardry's RPG elements are games that used to be called "Adventure Game Hybrids". I'll leave it to you to realize why...