Very anecdotal, but there are 64 SP* ($2mil or more) with 4L or 4R balance. 19 of them are "reverse" pitchers like Gregg. Here are there "over/under-priced" %s according to my NERP and eNERP formulas:
*positive scores mean "overpriced". Negative scores mean "underpriced"
**Cheaper players in the low $2mil consistently score as "underpriced"
LHP
V. Gregg (L) - $9.21 = -2.4%
P. Corbin (L) - $5.77 = 10.0%
D. Brown (L) - $5.65 = 6.0%
A. Downing (L) - $2.36 = -3.1%
R. Watts (L) - $2.01 = -10.8%
RHP
J. Arrieta (R) - $11.11 = 5.0%
J. Verlander (R) - $9.07 = 7.5%
B. Saberhagen (R) - $7.42 = 5.4%
J. Barnes (R) - $5.50 = -2.5%
D. Stieb (R) - $5.18 = 1.7%
P. Jarvis (R) - $5.05 = 3.6%
J. Palmer (R) - $5.04 = -2.7%
G. Gentry (R) - $4.96 = 4.8%
M. Moore (R) - $4.81 = -8.7%
D. Martinez (R) - $4.71 = 0.3%
K. Tapani (R) - $4.12 = 9.6%
S. Blass (R) - $3.27 = -11.3%
B. Anderson (R) - $3.18 = 3.9%
A. Sele (R) - $2.33 = -11.0%
So pretty mixed, but Gregg is a slight value

Nothing can dethrone Randy though
I just separated out all the "uneven" SP* at $2mil or greater and will analyze this weekend.
206 "reverse" SP*
71 of which are meh 1L/1R
54 are 2L/2R
39 are 3L/3R
19 are 4L/4R
9 are 5L/5R
7 are 6L/6R
5 are 7L/7R
1 is 8L/8R
1 is 9L/9R
With the new %vsL and R for LHP and RHP, these reverse will likely become better values within "uneven" pitchers. I believe Hack's comments are mostly off of labratory's breakdown of ACTUAL outcomes within the Sim engine. If Hal ends up playing them a certain way, that's more valuable than my supposed valuation.