Most of office is pretty replaceable, but the two bits that aren't are Outlook and OneNote. OneNote is semi-niche so it's not as pressing, but I would strongly disagree with the notion that Thunderbird is a replacement good for Outlook.
Seeing what practiced Outlook users can do is really eye-opening; it's a tool a lot of nerds (including me) hate, but it is a really powerful information management tool and I don't think Thunderbird (or anything else, including Evolution). I don't think I've found anything that is, though the full Google Apps suite does a decent enough job for my personal, non-work purposes.
Ex outlook power user here. Sorry but outlook is almost certainly used wrongly by most people. Its used as a filing system rather than a communication tool.
Mutt is just as useful if you don't mind not getting cat pictures.
We have a public JIRA instance. Everyone uses it or gets told to piss off. An email results in either a ticket being raised and is deleted. inbox zero. It handles the entire organisation's processes and rules and most importantly audit trail.
Scheduling is handled by an ical server which has feeds from jira. People use ical, their phone or mozilla's calendar software which I can't remember the name of.
Documents live in svn.
All of this is backed with centralised authentication via active directory/ldap.
There is nothing else. Outlook is the wrong tool for most jobs.
You do not get to tell users that they use a tool wrongly if it effectively serves their purposes. It's great that a Jira-based solution works for you, but that does not make it "right"--it makes it work for you.
Your attitude is why normal people hate IT people.
Hell yes you do if it doesn't comply with the audit, security and distribution requirements of the organisation.
Outlook effectively shoots all of the above without massive customisation which is expensive, ineffective and has so many edge cases it's unreal.
People hate IT people because they don't like being told what to do and don't like learning how to do stuff which is outside their comfort (read incompetence) zone. When it comes to handling your company's data, doing what you are told to do and following the process is the law.
The integration is what sells it, for sure. Between Exchange and Sharepoint, you have a really nice solution for normal/non-techie workflows. I hate it, but I also am pretty comfortable with alternatives and do most of my own stuff in a terminal and browser.
Seeing what practiced Outlook users can do is really eye-opening; it's a tool a lot of nerds (including me) hate, but it is a really powerful information management tool and I don't think Thunderbird (or anything else, including Evolution). I don't think I've found anything that is, though the full Google Apps suite does a decent enough job for my personal, non-work purposes.