(1) Doesn’t natively support push business email or over-the-air calendar sync. … The iPhone can sync with Microsoft’s Exchange and IBM’s Lotus Notes over IMAP and SMTP ports, but your server and security admins have to configure their infrastructure to do so or purchase a mobile gateway from Synchronica or Azaleos….
(2) Doesn’t accommodate third-party applications, including those internally developed. … This is a showstopper for companies with enterprise mobility initiatives that require line-of-business applications like mobile sales force automation or an industry-specific application like mobile claims…
(3) Doesn’t support securing data on the device through encryption.
(4) Can’t be remotely locked or wiped in the event of a lost or stolen device.
(5) Lacks a hard keypad that provides feedback, which isn’t ideal for rapid and accurate input.
(6) Has limited service provider support and its carrier lock-in inhibits flexibility.
(7) Comes with a premium price tag.
(8) Is only the first generation.
(9) Lacks a removable battery, so when the battery kicks it, so does the device.
(10) Lacks case studies of firms that have deployed it enterprisewide.

This list has been severely truncated.
To read the full list and text, please visit the original article:
Top 10 reasons IT won’t support the iPhone (Fortune)