Edelman was a slot guy. Playing a little outside late in his career when he and Tom had a unique connection doesn’t change that. He did most of his work in the middle of the field. There’s no rule saying slot guys can’t flex outside.
And slot guys also don’t have to be small as a requirement, they just need to have great agility, the ability to get open in short space and find soft spots in the zone. Jakobi Meyers was 6’2” and did the job well.
Controlling the middle of the field is a tenet of the Ernhardt-Perkins system. It went all the way back to the 80’s Giants with Phil McConkey, up to the Pats and Troy Brown… it was not McDaniels or his system… but the slot position is certainly a thing.
It was largely precipitated by bad weather (snow, rain) conditions and wanting to keep the passing game close to the QB. Outside receivers created the threat with speed and physicality, which allowed slot and TE’s to control the middle of the field. This hasn’t changed.
Bottom line, Brown and Doubs are the best threats outside, Douglas is the best, most difficult cover inside because of agility and explosion. This is why Boutte is behind all three… even if the team forces him into the lineup out of respect.