Currently only the main user-account (=system-user) can get access via SSH. Additional users and ftp-users only have access via FTP.

Please allow setting up additional users using SSH as well.

It would be great to have ftp account with an expire date.
A sort of temporary ftp accounts.

This becomes really usefull when you need to share your ftp details temporary with a webdeveloper, or somebody else to maintain of check an website.

I always make a new FTP account for this sort of events, but then forget to delete them. It would be real nice if you could set a expire date that the account automaticly blocks itself after that date is past.

Review an email's delivery route like Track delivery of Cpanel

Add an option to exclude domains / clients / resellers from a backup to the Plesk user interface.

Currently, it is possible only via command line:
http://docs.plesk.com/en-US/12.5/advanced-administration-guide-linux/backing-up-restoring-and-migrating-data/backing-up-data/specifying-data-for-backing-up.68839/

Currently the main domain must be renamed to change the main domain. This is cumbersome, especially if e-mail addresses are still assigned to this domain, because they will be also renamed. It would be more convenient if another already existing domain could be set as the main domain, e. g. by clicking on a button "Set as main domain".

Many times I find that some subscriptions won't sync because they are locked. I'd really like to know why they are locked. So far, I've been able to unlock & sync with no noticeable changes. But I'm left wondering what caused the lock in the first place. And I'm afraid that I'll realize later something no longer works as expected.

Please compile nginx with these extra options to provide even faster time-to-first-byte responses on modern kernels:

./configure ... --with-cc-opt='-DTCP_FASTOPEN=23'

Background information and complete guide: https://www.masv.io/enabling-tcp-fast-open-nginx-centos-7/

This would allow you to see mailboxes that are no longer in use.

Free version of Enterprise Litespeed, it would be nice to use lsphp+Openlitespeed+LSCache (free) within Plesk.

Having multiple DNS Templates, ideally selectable in a Service Plan, would add a great deal of flexibility in Plesk. For example, we have one type of Subscription that involves external store-and-forward mail servers for email backup. When a customer selects this type of Service Plan we have to manually adjust the DNS records to point to the appropriate mailservers. So it would be great if we could define multiple DNS Templates, then select the appropriate template in the appropriate Service Plan.

It would be great if it would be possible to create multiple users which can use the Git repository. Today only one user can access the Git repository. It is the admin user which was created during the creation of the subdomain. New created Web Users for the subdomain can not access the Git repository. It is a feature which I am missing because I wanted to host a private Git repository for our small private team.

https://talk.plesk.com/threads/can-not-create-new-users-for-local-git-repository.342409/

A carddav and caldav Server

The implementation of the centralized smartermail in plesk onyx for windows is good, but it should also be possible to integrate this feature into the linux edition.

Many hosters provide both windows and linux hosting with ONE centralised mail solution. Since the integration for winodws is already done I suppose it shouldn't be too hard to integrate it into the linux version as well since smartermail is completely API based.

Please Do allow to create RDNS(reverse DNS) records to the users for their mailing severs.

Many other Service providers have easy setup for that like: http://www.rackspace.com/knowledge_center/article/rackspace-cloud-essentials-creating-a-reverse-dns-record

Thanks

Allow users and admin to select subject lines and keywords as well as keywords in the email body to be added to the spamfilter blacklist.

Currently spammers are just changing domains and sending the same email templates.

A customer would like to be able to assign different PHP versions for different directories inside one the the same webspace.
For example,
/var/www/vhosts/example.com/httpdocs - php5.3.3
/var/www/vhosts/example.com/httpdocs/test - php5.2.17
/var/www/vhosts/example.com/httpdocs/test2 - php5.6.12

drupal support like wordpress

I would love to use exchange server 2013 while using plesk panel. Exchange server is by far the most superior email server for windows and would be a great addition to plesk panel.

I believe that there is also an open API or an easy way to send commands which would make it a lot easier to integrate with.