Considering that the "Origin" system continues in BG3, you might suspect that players enjoyed using it in DoS2. The argument that the custom characters were shallow doesn't make much sense in this case. Most people didn't even know it when they first played it, but the system would still have to be popular (most people don't even finish games, not to mention playing a few times.). If it were otherwise, Larian would not waste resources to introduce a mechanic that not many people like.
Could use some statistics from DoS2 how many people finished the game as a custom character. It may turn out that the "origin" system may have been more popular than we think.