Well, think about it. What you're saying is that you want an indication that new data is available so that you can then chose if you want it or not. But... isn't that what happens when you turn Overwrite on? It shows you a color when there's new data, and then you can chose to SAVE or REVERT it.
I think it comes down to management by exception, and which is the more common action.
The first time you run MCR, you want it to load in all this new data you didn't have before, so lots of overwriting.
But after you've loaded your initial data, you make tweaks in MC. You have posters you don't want overwritten, for example. Or you make changes to the order of the actors field so that silhouette pictures come later.
Now you're in maintenance mode. Now overwrites become the exception rather than the rule. Mostly you want your existing data preserved. There are two ways of dealing with this in MCR: change the overwrite default, but now you will never be notified of updated data, or leave it enabled but you have to revert a bunch of fields, which is lot of clicks.
Yes you can lock fields, but then you also do not get notified of an available update.
You said "For posters, Orange means that there's one with higher resolution available."
Except that does not work if overwrite is disabled. And it's not just posters, it's all fields.
If overwrite is disabled, or if a field is locked, you get zero notification as to new data, no matter what field it is. That's bad, so I think there should be a color for that.
What would be best is if there is new data available for a field that has overwrite disabled (or is locked) then you get some notification... maybe it blinks. And then you could right click on it and click "Accept new data anyway".
Locked fields are hard to spot. It would be nice if you could filter for them. There are so many cells in a row, and so many rows, that being able to filter by condition (locked cells, changed cells, cells where new data is available but inhibited) would be very helpful.
Bottom line is that what I'm calling maintenance mode, management by exception, where changing an existing value is only sometimes desired, is a pain in MCR, because you essentially cannot do it unless overwrite is enabled for all fields. So then you have to lock, or do a whole bunch of reverts.
Think about it in a similar way to software updates. If a user's policy is "I always want to be notified when new updates are available, but my default position is not to take them." That can't be done in MCR, because to get the notification overwrites must be on. And because you can't selectively push to MC, you must explicitly reject the 99 updates you don't want, instead of accepting the one you do. That's the opposite default from what you want.
It just makes some modes of use more difficult than they need to be. An additional color code to indicate an update is available but inhibited would be helpful in mitigating, as would selective writes to MC.
Thanks...