Ian's untimely death preserved the legacy of JD. Joy Division never had to suffer the embarassing demise that many bands put us through. How far and in what driection would they have gone?
Personally, I think his vocals would have limited tha band to some extent. Too dark, too strange, something not quite right. Yet they were perfect for JD. Barney's, on the other hand IMHO, are much better in terms of appeal and aesthetics. Look at Stan Ridgeway.