Flights of Fancy
Candy is King
We never went quite that far with it, but yeah in that direction.If thief skills allow you to do things no one else possible can, the dynamic changes completely. For example, if a thief is hiding in shadows, I treat them as being invisible to basically everything other than True Seeing. Unlike magical invisibility, their invisiblity cannot be dispelled or detected.
Like most classes, the low levels everyone was reasonably weak lol---at least until UA came out.I still consider that thieves, especially at low levels, as a reasonably weak class, but they are certainly not useless.

Thieves were very niche in 1E with low HD and mediocre combat table (IIRC cleric was better?), but since they had a role no one else could really do, they were fun and (I agree!) certainly not useless.