If we're talking what kind of depth Croom left, let's look at the 2009 post-spring depth chart.
QB 16 Tyson Lee, 5-10, 200, Sr.
14 Chris Relf, 6-3, 235, Soph.
Lee was Lee--he outperformed his talent and is a great person. But Croom left us a walkon QB as our starter. I give Croom no credit whatsoever for Relf.
RB 24 Anthony Dixon, 6-1, 235, Sr.
29 Christian Ducre, 6-0, 220, Sr.
30 Arnil Stallworth, 5-9, 205, Sr.
Solid talent here, but MSU has never lacked for RBs. We've done as well or better under Mullen.
WR(X) 6 Brandon McCrae, 6-4, 200, Sr.
8 Leon Berry, 6-0, 190, Jr.
Decent here but hardly top end talent.
WR(H) 19 Terrance Davis, 5-11, 185, RFr. OR
5 Delmon Robinson, 5-9, 180, Soph.
Both wound up transferring.
WR(Z) 81 O'Neal WIlder, 6-5, 190, RFr.
83 Charley Bailey, 6-1, 180, RFr.
28 Tay Bowser, 6-3, 200, Sr.
Wilder quit for track. Bailey wound up at Grambling. Bowser tried out for the Ravens as a CB but was not spectacular here.
WR(Y) 88 Kendrick Cook, 6-4, 250, Soph.
85 Brandon Henderson, 6-2, 245, Jr. OR
87 Thomas Webb, 6-4, 230, Jr.
Cook was mainly a special teams guy. Neither Henderson nor Webb did all that much.
LT 79 Derek Sherrod, 6-7, 310, Jr.
63 Chris Spencer, 6-4, 310, Sr.
Sherrod is Sherrod. Spencer never played much.
LG 55 Quentin Saulsberry, 6-3, 300, Soph.
75 Craig Jenkins, 6-5, 315, Sr.
Young NFL talent backed up by a senior.
C 70 J.C. Brignone, 6-2, 300, Jr.
66 D.J. Looney, 6-2, 300, Soph.
Brignone was won of my favorites and a solid player, but Day is just as good or better. Looney would become a student assistant.
RG 67 Tobias Smith, 6-4, 310, RFr.
74 Mark Melichar, 6-4, 300, Jr.
Smith was great but hampered by injuries. Melichar was a career backup.
RT 62 Addison Lawrence, 6-5, 295, Soph.
76 Phillip Freeman, 6-6, 300, Jr.
Lawrence turned out to be solid under Mullen. Freeman was a career backup.
LE 99 Sean Ferguson, 6-3, 245, Soph.
36 Nick Bell, 6-3, 250, RFr.
Ferguson was solid. Bell, of course, died too young.
LT 95 Kyle Love, 6-1, 310, Sr.
92 Charles Burns, 6-1, 275, Sr.
Love to NFL; backed up by a senior.
RT 90 Pernell McPhee, 6-4, 275, Jr.
91 Rodney Prince, 6-0, 265, Soph.
I guess McPhee practiced at DT, which I had forgotten. Not sure what became of Prince.
RE 93 Brandon Cooper, 6-1, 255, Jr. OR
54 Trevor Stigers, 6-4, 255, RFr.
McPhee would become the end. Not sure what happened to these other two.
SLB 34 K.J. Wright, 6-4, 245, Jr.
45 Michael Hunt, 6-3, 240, RFr.
Wright to NFL. Hunt quit.
MLB 22 Jamar Chaney, 6-1, 245, Sr.
44 Bo Walters, 6-0, 240, Soph. OR
33 Jamie Jones, 6-0, 235, Soph.
Chaney to NFL. I'm not sure what became of the other two.
WLB 50 Chris White, 6-3, 245, Jr.
49 Terrell Johnson, 6-2, 205, Soph. OR
52 Karlin Brown, 5-8, 200, Jr.
White to NFL. I'm not sure what happened to Johnson or Brown, but they never started.
LCB 26 Damien Anderson, 5-11, 195, Soph.
20 Louis Watson, 5-10, 180, RFr.
Backups after Banks emerged.
SS 4 Charles Mitchell, 5-11, 205, Soph.
48 Emmanuel Gatling, 6-0, 210, Jr.
Mitchell to NFL. Gatling was a walk on playing above his talent.
FS 42 Zach Smith, 5-11, 200, Jr.
7 Wade Bonner, 5-9, 200, Soph.
Zach Smith could really take a lick. Bonner was a decent contributor.
RCB 18 Marcus Washington, 5-10, 190, Sr.
25 Corey Broomfield, 5-10, 165, RFr.
Washington got beat out. Broomfield was recruited by Croom but developed under Mullen.
So, let's compare 2009 spring and 2013. In 2009 we had a poor QB situation salvaged by Mullen; after some ups and downs recruiting we now have a solid passer backed up by dual threat guys who look to be doing well and two solid recruits on the way. Mullen has done as well or better at RB. OL was in a poor situation beyond the starters in 2009. Mullen struggled in OL recruiting for his early years but now most of our starters will return in 2014 with a decent group of underclassmen behind them. WRs Croom left were mostly bad and the position was largely staffed by underclassmen in 2009. We seem to be picking it up there as well recruiting wise.
On D, to Croom's credit we had three NFL players at LB in 2009. But they were backed up by nobodies. We now have another solid group of LBs with great depth at the position. Croom left us in a poor situation at CB and we were saved by Banks and Broomfield, who were developed under Mullen. We now have what appears to be a solid group at CB. Mitchell was a good safety, but we have talent there now as well with Whitley, Hughes, Antoine, and Arrington. On the DL, Croom left us with Love, Ferguson, and Bell followed by nobody. Mullen filled in the gaps with freshmen and JC transfers. We now have Jones, Jones, Evans, James, Eulls, et al all with potential.
IF Mullen were to leave at the end of the year (he won't, but for the sake of the argument), whoever replaces him would come into a pretty good situation personnel wise. By far better than Croom on the whole despite the decent high end talent he left.