Like I said, the book isn't in freefall (16,148 is just 0.6% down on the previous month's 16,242.) On a strict percentage basis, it's actually very stable.
The problem isn't the current rate of decline, it's the cumulative declines that have gone before. Think of it not as a plane rapidly crashing to Earth, but a disabled submarine nearing the point, ever-so-slowly sinking downward, where the pressure will crush it.
Also to put the low CBS orders here in perspective, it's not just the Legion title that is hurting but the entire DC mid-tier titles order numbers are in free fall. Many are chalking that up to extreme editorial meddling - in particular from Bob Harris.
Well, let's turn the perspective into context. Here's all the DCnU titles I can see from March on the chart:
March 2013 DCnU titles:
100k+
3. BATMAN #18 ($3.99) - 137,893
6. JUSTICE LEAGUE #18 ($3.99) - 102,494
90k+
9. JUSTICE LEAGUE OF AMERICA #2 ($3.99) - 91,734
80k+
(none)
70k+
18. DETECTIVE COMICS #18 ($3.99) - 76,237
60k+
19. GREEN LANTERN #18 ($2.99) - 69,801
20. BATMAN AND ROBIN #18 ($2.99) - 69,614
23. BATMAN INCORPORATED #9 ($2.99) - 64,067
24. ACTION COMICS #18 ($4.99) - 61,879
50k+
27. BATMAN THE DARK KNIGHT #18 ($2.99) - 54,269
28. AQUAMAN #18 ($2.99) - 53,337
30. BATGIRL #18 ($2.99) - 51,677
40k+
34. SUPERMAN #17 (
LATE, $2.99) - 49,666
37. SUPERMAN #18 ($2.99) - 48,236
38. NIGHTWING #18 ($2.99) - 48,223
42. EARTH 2 #10 ($2.99) - 46,213
46. GREEN LANTERN CORPS #18 ($2.99) - 44,215
50. TEEN TITANS #18 ($2.99) - 42,055
51. GREEN LANTERN NEW GUARDIANS #18 ($2.99) - 42,028
54. FLASH #18 ($2.99) - 41,659
30k+
60. WONDER WOMAN #18 ($2.99) - 38,406
61. RED HOOD AND THE OUTLAWS #18 ($2.99) - 37,731
62. CONSTANTINE #1 ($2.99) - 37,564
68. RED LANTERNS #18 ($2.99) - 35,203
69. BATMAN INCORPORATED #8 (
REPRINT, $2.99) - 34,679
73. CATWOMAN #18 ($2.99) - 33,220
76. BATWOMAN #18 ($2.99) - 31,381
77. SWAMP THING #18 ($2.99) - 30,716
20k+
81. ANIMAL MAN #18 ($2.99) - 28,711
82. WORLDS FINEST #10 ($2.99) - 28,469
86. GREEN ARROW #18 ($2.99) - 28,080
87. SUPERGIRL #18 ($2.99) - 28,051
90. JUSTICE LEAGUE DARK #18 ($2.99) - 25,664
93. TALON #6 ($2.99) - 25,440
94. SUICIDE SQUAD #18 ($2.99) - 25,232
95. SUPERBOY #18 ($2.99) - 24,455
103. BIRDS OF PREY #18 ($2.99) - 21,957
10k+
113. LEGENDS OF THE DARK KNIGHT #6 ($3.99) - 19,681
114. KATANA #2 ($2.99) - 19,247
115. JUSTICE LEAGUE OF AMERICA #1 (
REPRINT, $3.99) - 19,225
116. JUSTICE LEAGUE OF AMERICAS VIBE #2 ($2.99) - 19,092
123. PHANTOM STRANGER #6 ($2.99) - 17,375
126. ALL STAR WESTERN #18 ($3.99) - 16,897
132. LEGION OF SUPER HEROES #18 ($2.99) - 16,148141. THRESHOLD #3 ($3.99) - 15,109
148. RAVAGERS #10 ($2.99) - 13,466151. STORMWATCH #18 ($2.99) - 13,255
157. DIAL H #10 ($2.99) - 13,084
160. DEMON KNIGHTS #18 ($2.99) - 12,975
166. DEATHSTROKE #18 ($2.99) - 12,306168. BATWING #18 ($2.99) - 12,084
170. SAVAGE HAWKMAN #18 ($2.99) - 12,021172. TEAM 7 #6 ($2.99) - 11,805173. SWORD OF SORCERY #6 ($3.99) - 11,776176. DC UNIVERSE PRESENTS #18 ($2.99) - 11,679178. I VAMPIRE #18 ($2.99) - 11,568188. FURY OF FIRESTORM THE NUCLEAR MAN #18 ($2.99) - 10,679<10k
237. HUMAN BOMB #4 of 4 ($2.99) - 6,379