IMCE 2 makes some very good inroads towards proper file management, including hook_file() support and reference counting. In, ufku suggested enabling all IMCE features like uploading and file deletion when using the 2.x version of the module. I think that IMCE is still a little too liberal with its options (such as allowing uploads to be created anywhere) such that some control is still needed to prevent unwanted creation of thumbnails and uploading of files.
So in order to enable uploading/deletion in IMCE 2, I think we just need a few configuration options in the IMCE FileField Source settings:
IMCE Mode: (•) File browser only ( ) Full IMCE profile (uploading, deletion, thumbnails, etc. if allowed)
Fine-grain control of options would be locked down through the normal IMCE profile settings.