In your post I've highlighted the parts where the sentences converge in opposite directions and completely contradict each other. How you think in act in the game is the role-playing in the social sense. It's entirely different and completely irrelevant to your skillset, and your skillset is also an aspect of roleplaying. The skillset defines the talents of your role, and how you behave defines the "personality" of your in-game character. If the skillsets are being dumbed down then there'll be less distinction between different characters you make.
Nothing's stopping my mage character from stealing that staff on the table. The skills only show if the choices our roles make will be sucessful or not. Skills are a neccessary evil, and I really don't like them. Less...more, skills don't make a game an rpg. They show what a character can and cant do. The game will be an rpg, albeit a bad one, even if there were no skills at all. You could go around, still steal stuff, fight things with swords, craft things, talk to people. You'd still be able to do it all. There just wouldn't be much reason to play, cause there would be no feel of progression.
The reason there are numbers in rpgs in the first place are just for that, so there is a feel of progression. It has little to nothing to actually do with the rpg aspect. It makes sense that a thief would get better at being sneeky the more time he spent sneeking around, but how does one implement that into a game? I dont know, sadly. That's why numbers are a needed evil. They give your character a sense of progression, and perks will also be doing the same.
You made a choice at the beginning of the game to be a thief. All the characters start with a blank slate. Is a thief at the beginning of the game any less of a thief towards the end of the game? Well, no...not really. The thief towards the end obviously is going to be better, but they're both still theives. The numbers just show the progression, that don't have anything to do with the role itself.