With that being said - do you, or do you not realize the difference between "simulating objects in physical space and seeing if they clash" and "rolling a dice, and the number that comes up determines if it's a hit or not"?
So..you don't like "simple" common stat&checks system - and you ask for more advanced one, with more stats and more checks?
"Simulating objects in physical space" would take same checks, but require more of them. And they still will include player stats and skills - those are not going anywhere.
Be it 2d6+str or some crazy formula which respects blade type and shape, weight, possible hit angles, surrounding temperatures, humidity and lighting - you can NOT model it without adding player stats (and also enemy defence - type, material, features) variables into calculations. Unless - "always hits and damages".
I can't get it. You don't like d20 rolls, but you just offer to add some more...
And if you care so much for "realism" - my husband rides bike for something like 30 years, and month ago he fell and broke his arm. So..no - random things are not that unreal as you may think they are.
But let it be, even if you do "simulate" swordfight in some supersimulating realistic manner.... HOW can you "simulate" social skills in a single-player prescripted game (without using stats and skills)?
If proving things were that easy - lawyers would never have a job. Knowing facts and being able to use them - is a different thing. Pretty face does not make you charming.
Obvious DA2 example - you can not trick templars and tell them to leave, Varric - can. You both know same things. Varric has skill, you...have only Varric. Game does not check how smart Hawke is - it just checks did you take this allmighty storryteller in party. Game does not allow you to be persuasive yourself.
So while this can still be implemented, it seems somewhat irrelevant, if all the other dialog options are also viable solutions.
You know, talking Saren to suicide was also pretty much optional. It does not change game outcome. Same as conversation with inspecting admiral (Mihalkovich afair) could turn pretty much different if you use and if you don't use skill lines. Or - DAO, freeing Sten. 3 options to have same outcome. Pick, talk, intimidate. So - yes diplomacy and charm was always just an option. But you could have this option if you needed it.