The need for interfaces will somewhat diminish as users begin to exploit the agents or rules that are already built into some mail systems and are sure to show up in others. Agents can help filter and order mail, separating informational gold from useless dreck. The trick with agents will be to build interfaces simpler than those in current e-mail products. Distributed object stores, like the one in Lotus Notes and the one planned for Microsoft's Cairo, will go a long way toward giving all users access to single copies of live, editable attached or embedded items like word processing documents, spreadsheets, database applications and graphics. System types don't have it any easier with messaging.
Installation can be a nightmare, especially when gateways to other mail systems are involved.
Management is frustrating since most systems lack good tools to do even simple tasks like disk space usage control and message tracking, let alone full e-mail network system management. Like user interfaces, management will get better. Gateways will be more tightly integrated into mail systems, making their installation easier. Folder and directory replication will be commonplace in e-mail systems in a year or two. Common distributed object stores will make it easier to manage data across multiple location e-mail systems very soon.