Sanskrit a and Indo-Iranian palatals

Misra's bold formulation proposing a great antiquity for Sanskrit a
and questioning the Law of Palatals seems to be a winner.

Here is the central issue.

In the Univ. of Mich. conference, 1996, Misra was criticised by Hock
by special invitation without giving Misra an opportunity to rebut.
Now Misra has delivered 10 lectures reiterating his views and
proposing that IE homeland could likely have been Bha_rata.

Hock (1996 U Mich conf.) criticized the earlier views of Prof.
Misra: `…Indo-Iranian palatalization can only explained if we
reconstruct an earlier stage with contrasting e- and a- or a- vowels.
As noted earlier, it is this evidence which provides crucial support
for reconstructing Proto-Indo-European with a triple contrast e:a:o
and for assuming that the corresponding single a vocalism of Indo-
Iranian results from the merger…' (p. 11 in: Bronkhorst and
Deshpande, eds., Aryan and Non-Aryan in South Asia).

Prof. Misra counters this in Lecture 6 (1999):

The change of Iranian a in Avestan may be shown as follows:
Examples:
1. a > A when followed by m,n,vi_ but preceded by any sound
except y,c,j,z~
Av kAm cp Skt kam: Av barAn cp Skt (abharan; Av sAvis~to cp Skt
s'avis.t.hah
2. a> I when followed by m,n,vi_ and preceded by y,c Av yim cp
Skt yam: Av va_cim cp Skt va_cam; Av drujim < Iranian drujam cp Skt
druham <*drujham; Younger Avestan druzinti < Iranian drujanti cp Skt
druhyanti
3. a > e after y when immediate next syllable had I_,e,y,c,j or
Nh (=Skt sy) Av yeidi/yedi cp Skt yadi; Av yehe/yeNhe cp Skt yasya;
Av iTyajah cp Skt tyaj; Av yesnya cp Skt yajn~iya
4. a > o sometimes after labial sounds when the next syllable
had u/o Rarely also a>o when the next syllable had a conjunct
preceded by r. Av vohu cp Skt vasu; Av mosu cp Skt maks.u; Av pouru
<*poru (<Iranian paru < Iir pr-ru) cp Skt puru; Gathic Avestan corAt
<*cort <*cart cp Skt kah <kart
5. a > a in all other situations Av apa, cp Skt apa; Av asti,
Skt asti.

The change of a to several vowels a,e,o etc in Avestan was
conditioned by definite situations. But the change of a to a,e,o in
Greek, Latin and to a,e in several other languages was a change for
which no condition can be determined. This shows that these languages
belong to a much later date, when there were generalisations and
several other phonological and morphological changes.(pp.46-47).