Based on your response, it appears your biggest problem is not in MS Project. Your bigger problem appears to be an unstable operational environment resulting in an unpredictable operational work load that regularly consumes all your available resources, leaving minimal to no time for project work.
Operational or “keep the business running” work is definitely highest priority. I would suggest that you have several courses of action that must be discussed and agreed upon with Sr. Management.
* Stabilize operational work. No new projects until the operational work is under control and somewhat predictable. You might need some root cause analysis here to determine what is actually causing the operational issues so those root causes can be fixed, as opposed to constant on-going patching.
* Dedicate existing staff to operational work, obtain new resources that would be dedicated to project work. Yes, this means adding resources, which management often doesn’t want to do. Note these could be contract resources or full time and contract resources could be assigned ownership of stabilizing the operational environment, which means they could be whittled down over time as less and less operational work is needed.
* Get management to accept/sign off on the current environment. Meaning operational work may consume all resources and project work will never be predictable and may never get done. (probably not acceptable)
Either way you look at it, it appears the problem is too much work for available resource capacity.
Sr. Management should help set, agree to, and then help you manage towards an operational/project work distribution goal. For example, Management may want a 20/80% work split for operational/project work. The key is defining what they think is an acceptable operational work ratio, agreeing on a plan to get to that ratio, and setting an organizational goal to obtain that goal. How you get to that goal is not as critical as recognizing the root issues and addressing them.
Unfortunately, I don’t think there’s anything you can do in MS Project at this time that will help you manage this. You can be an MS Project expert with the coolest, most sophisticated schedule, but if the resources aren’t available to do the work, the schedule is irrelevant.
Hope this helps