Not an issue, a required designed feature that worked as intended.
Bethesda wanted to bring definition to the PC. As they also maintain the connection between action and consequences (the PC is what they do, contrary to some other products PCs are disconnected from what they do, distribution of points over a list with no connection of past action), the fast levelling feature provided what was expected.
The defining in PCs would lead to PC extremelly proficient in stuff while inept at other stuff.
Fast levelling acts as hinderance: players who want extremelly proficient characters must avoid dabbling in other stuff as every single level put in other stuff was taken out of the other levels.
Behind all this, there're of course higher stakes as defined characters would enable de PC centrization of a gameworld and introduce a new array of reliance over the gameworld.
Like a totally inept in stuff PC must rely on the gameworld to produce what is required, the PC unable to centralize everyting.
Bethesda's problem is not providing functional systems. It is providing functional systems serving purposes players do not like.
Players do not want definition. Players want to be anything they want with no other constraints that the constraints they impose. No constraint must come from the game.
Removing the cap limit (that gave meaning to the defining act) was one of the first demand.
Hence Fall Out4's measures: Bethesda do not start with a feature they know players reject.
It remains though that they keep talking definition of characters so if they are on that, the defining must come from other means.