We are requesting the ability to add more than one requester to an incident, problem, etc...

Why do we want this?  As others have already posted, there are many valid reasons for needing more than one requester on a ticket.  Our main reason is the scenario where more than one resource in the organization needs to be kept informed as to the progress of an incident.

Ex. A customer (a very important customer) reports that our product, or a particular feature, is "running slow".  The requester on this ticket might be one of our internal support reps, but we need the following to be informed of the progress of this ticket and notified when notes/comments are added, or the status is changed: our sales rep for this customer, our VP of Operations, our President (remember this is a very important customer!).

If you prefer, changing this feature request to something like "Add Watchers", where a "watcher" is a new field and relationship type that would have the same trigger and notification capabilities as are available for a requester.  I don't know the inner workings of your system, but a "watcher" might be a less complex change for you than modifying existing functionality for "requesters".

An alternative solution would be the ability to select one or more additional users to notify when adding a comment or updating ticket status.  This would achieve the same result we desire, but is susceptible to manual error (forgetting to cc an interested party) and is not a clean of an implementation as allowing multiple requesters.

Excluding this functionality being added to the product, is there another solution or workaround to what our needs are?

Note: I have seen ManageEngine feedback on other threads on this topic that a group or email address could be created, where that group or email contains everyone that needs to be notified.  This is not a realistic option for us as we'd have to create so many unique combinations and keep track of who is on each one - would be a nightmare to manage and remember.

Last comment: The other ticket systems I have used have offered this functionality and it appears this is a common and repetitive request from your current customers.  So far, this is the only missing SP On-Demand functionality that is impactful enough on our needs that we would consider switching to a competing product vendor.