I believe that it would be eminently possible through a subclass (although as ever, I think that subclasses should start from level 1). Possibly siimilar to the Inquisitive, but with less emphasis on spotting deception and more on knowing stuff.Backward focus.
If the rogue doesn't get the skill it can't improve its application.
Also this sucks up the customization option for known lores by taking up the background.
The Scout for example gains two skills and expertise in them.
Its pretty much a mechanical representation of the bare-knuckle fight in the Sherlock film. Observe. Predict. Tailor a strategy. That does not come across as underhanded to me.It's the closest one. Unfortunately it feels too much like an underhanded scoundrel still and the rogue base class snags too much off the design phase for improvement in lore.
I think that you're going to have to unpack this a little to explain it to me. The rogue does not need to be sneaky any more than than it needs to be athletic.The issue is the base class. The 5e rogue is a sneaky sneaky class not a loremaster class.
Do you want to create an intelligent and charismatic character with a wealth of knowledge useful to the group, or do you just want a combat murder machine? If you want the loremaster character, dumping Intelligence is suboptimal.Because the way I want to build the character is blatantly suboptimal for any noncaster? The Primary, secondary, and tertiary scores as the mental ones.