Is it a good idea?
Yes, it seems like this would be a good way to ensure that your UI would always reflect the current state of the data store if all modifications went through your model. Are your program and the plugins the only way to modify your data store? If yes, then it would simplify things if all modifications could go through your model. Since modifications would be queued, I do not think the state of your data store could get out of sync. You might have to lock reads whenever a write is in progress to ensure that no client got a bad record.