springrollsruwin in HL first showed the benefit of just tanking heals on the scout class, I think also in 6s as well but I'm less confident on that front
iirc botmode was reviewing the top 100 NA players tftv and stated that ruwin was considered the first “pocket” scout, playing similarly to modern scouts in todays meta even without the medic move speed passive on heal target that was added WAY after he stopped playing. It was fairly impressive considering shotgun sollys were considered the carry class back then (or so I’ve been told) and which led to harbelu (playing pocket solly at the time) run gunboats.
Also my take for players/teams that influenced the community that weren’t froyo I’d say ruwin and the other classic mixup guys would definitely be up there like enigma making tftv, TLR marking the stereotype of buff soldier players, seagull and his methods of roamer, etc.