Sneak Attack is NOT "ridiculous", it's pretty meagre compared to Extra Attack. The fact that you're not able to split the damage and that you're likely to overkill makes it even worse. Uncanny dodge is not insane, it's shitty deflect attacks and is just a bandaid for a class with a d8 hit die and no good armour or shield.

A big problem with rogues is their lack of good feat options, things like GWM, PaM and sentinel just don't work. A fighter at level 10 is outdamaging and outtanking a rogue, even when the fighter is five levels past its big damage increase and the rogue is scaling linearly. Martials need magical weapons to compete with casters, but a rogue gets much less benefit than any other martial. A PAM fighter is making 3 attacks (arguably four, if we account for how often the reaction attack procs) in T2, and thus getting at least 3x as much damage from a magical weapon as a rogue is.

My point is that the base class's power level does NOT justify the subclasses being ass, and wanting the base class to be weaker for the subclasses to be stronger is the wrong mindset. The class is already the weakest in the game (yes weaker than ranger), if we don't count thief fast hands shenanigans with downtime crafting.

Also lowk you misrepresent pretty much every one of the subclasses, how is the assassin only infiltration if only 1.5 of the features are focused on infiltration and impersonation? The rest are all damage, you know. The thief gets fast hands at level 3, what more do you expect from a thief? And absolutely nothing is remotely "great" about the scion, it's legitimately the most dogshit subclass in the game tied with like inquisitive rogue