There's a difference between incoherant and unique. The basic parameters stay the same but allow for a great deal of room to create.
The rules can leave room for creativity, but then that creative space needs to be available for the player, as well.
I'm creating the character. I want the full set of rules available to me for that.
This isn't table top where uniformity is required.
Yes it is. The uniformity of tabletop isn't there because of the medium. The uniformity of tabletop is there because it makes for a better roleplaying environment.
And that's what these games should be trying to do - provide an environment in which we can roleplay.
It is a whole different medium. And slavishly holding to rules inhibits storytelling.
Roleplaying is storytelling. It's collaborative storytelling.
Moreover, I would argue that any form of narrative - even authored narrative - is harmed by a lack of internal consistency. If the setting doesn't hold together, it makes for either plot holes or deus ex machina.
But particularly the emergent narrative of roleplaying - that needs a coherent setting because the story is driven by the characters' decisions (like any narrative), but in a roleplaying game the authors aren't the only ones making them. The player makes decisions as well, and those decisions are informed by the setting in which the character lives. The player needs to know the rules that govern that character's world, and the character's decisions aren't going to make sense if the world in which he lives doesn't make sense.
As long as there is a logic to how the skill trees are put together (which there was in DA 2) it won't be a problem.
I think we have wildly different definitions of logic.
But I also hated DA2, so my assessment of its features is likely biased.