It doesn't sound as though they're removing IMAP. It's still the recommended API for mail client applications. This API is a new, separate option for applications that don't need access to all your mail.
Gmail don't implement IMAP properly anyway - the IDLE command in Gmail doesn't provide notification of changes in the number of unread messages, just the existence of new ones.
It was quite a shock to find when I stopped hosting my email via GetMail/Dovecot that my read messages wouldn't automatically propagate across my devices until I did a manual poll. Gmail seems to use some HTTP API for this rather then following the standard.
