He is 56th in career WAR for position players.
Walker is 30th in OPS for all players with 2500+ PAs from 1990-2005 in away games (.866). 19 guys had at least .900. Even at 3500+ PAs, he is just 19th. Is that good enough for the Hall?
This link has the data
Walker was 25th in away OPS during 1990-94 (Expos years) for guys with 1000+ PAs with .823. 7 guys had at least .900
One person on Twitter wondered about Hank Greenberg. He was 4th in away OPS using 2500+ PAs over the years 1933-1947.