Cuprajake Are these more similar to filter coffee than espresso? They lack body, give clarity and are usually quite high in volume output,
I often pull shots with lighter roasts around 1:4 to 1:6, (not “turbo”, supercharged, water injected, nor any other attempts to raise their BMEP). Yes, I feel the flavours are easier to pick out and the coffee is less generic & less sharply acidic (even at a reasonable EY, not EK levels as discussed in the Cameron paper cited - it is also worth noting in that paper thy say that people might not have a preference for the shots and mixing them with a 1:2 might be a highly impractical solution).
1:6 shots are still twice as strong as typical filter, 1:4 three times as strong, but yes, much lower intensity & mouthfeel than 1:2 shots.
For darker, more conventional espresso roasts/blends, I might be more like 1:2.5 to 1:3.5.
Longer shots aren’t a new idea, they got very short in the early days of specialty (1:1.5-1.6), but have been creeping up in length again in the last decade.
Illy, INEI and the SCAA all have a broad definition range, often centering around 1:3.5/4.0.