I went ahead and trained my guy up to 120 Healing and Anatomy, and tested regular vs. enhanced bandages 30x each (datasets below). Regular bandages averaged 57.4 hp; enhanced bandages averaged 59.6 hp -- a significant difference. Additionally, the enhanced bandage data set includes one instance of a 73 point heal and two instances of 72 point heals, which are ostensibly outside the range of 120 Heal/120 Anat but are consistent with 130 Heal/120 Anat (the regular bandage data set had a maximum heal value of 70, within the expected range).
Conclusion: Enhanced Bandages DO improve the healing rates of legendary healers, despite dev assurances to the contrary.
Expected range for regular bandages: 43-70 (56.5 average)
Projected range for enhanced bandages: 44-73 (58.5 average)
Regular Enhanced
53 63
66 63
50 44
69 73
45 68
67 69
53 51
68 67
67 64
48 45
52 45
61 72
58 59
70 54
64 45
54 72
46 65
55 59
50 61
45 69
50 61
65 49
63 59
57 55
50 69
48 64
61 50
55 65
61 53
69 45
Average
57.4 59.6