i think that's probably how it should have been pronounced at one point! i'm sure it's one of those words that's pronunciation has degenerated over time, but the spelling hasn't been revised accordingly (if that makes sense!)
as a child i hated spelling it - same with leicestershire etc. (pron. 'lestershire' of course), all very confusing!
for the record, i say worcester so it rhymes with 'duster'- i have a bit of a regional accent of my own but you get the idea! ;)