Can we find stats to back this up? I feel Murray is fairly aggressive too, often more than Djokovic who more often than not goes for the very effectice deep down the middle return
if we oversimplify 1st serve returning by saying aggressive/defensive returning depends on how often you get returns in play, and effective returning depends on getting your return deep (past the service box):
Djokovic: returns 66% of 1st serves, gets 78% of those deep, so against 1st serves he makes deep returns 51.48% of the time
Murray: returns 72% of 1st serves, gets 72% of those deep = 51.84%
other notable 1st serve returners of the past couple decades:
Ferrer: 66% x 76% = 50.16%
Medvedev: 70% x 75% = 52.5%
Davydenko: 68% x 74% = 50.32%
Federer: 66% x 74% = 48.84%
Nadal: 71% x 67% = 47.57%
Hewitt: 63% x 68% = 42.84% (?!)
great returners in the past:
Agassi: 57% x 68% = 38.76%
Connors: 59% x 68% = 40.12%
Borg: 74% x 52% = 38.48%
McEnroe: 73% x 62% = 45.26%
Wilander: 71% x 58% = 41.18%
Chang: 68% x 69% = 46.92%
Edberg surprisingly (to me) missed my arbitrary 38% cutoff: 67% x 56% = 37.52%
all stats from Tennis Abstract Match Charting Project
limiting variables: effective returning isn't just about getting it deep but even if it was, direction and how deep matters; used rounded numbers rather than using consistent significant figures, so keep in mind non-trivial margin of error; small/skewed match samples for older players, surface-biased players, and Murray; for some reason match charting stats seem broken with players like Alcaraz and Sinner so didn't include them here, but they should rank favorably