Makes sense. Here's something else to ponder.
Based on the cruise port schedules, you can see that Magic will do the Iceland cruise in late August in 2020. It might be a roundtrip from Dover or a repositioning cruise from Copenhagen. But, what does it mean for the Baltic cruises? Possibly that the 10-N Baltic might be moved up to July 2020 and - unfortunately - could sport a bigger sticker.
Alternatively, as the 7-N Baltic was very popular this year, they might replace the 10-N Baltic with an 8-N Baltic with an extra night in SPB. And reposition through Norway.
Something like this:
Second half of July: Reposition from Dover to Copenhagen through Norway or Baltic
First half of August: Two of 7-N Baltic, or 7-N + 8-N Baltic, or 7-N Baltic + 7-N Norway
Second half of August: Reposition back to Dover through Iceland
A repositioning cruise from Dover to Copenhagen in late July would be a very intriguing option. In our case, we're thinking of starting our 2020 vacation with a couple of nights in London. Originally, I was planning to then fly from London to Copenhagen and spend an additional two nights there before the cruise. But if they do a Baltic repositioning cruise from Dover to Copenhagen, we could simply take a train from downtown London to Dover on embarkation day and then maybe spend one night in Copenhagen after the cruise.
Cost differential will be a factor. Right now, the 10 night 2019 Copenhagen to Dover repositioning Baltic cruise isn't much more expensive than the 7 night Baltic cruise that starts and ends in Copenhagen (and if the 2019 cruise was from Dover to Copenhagen instead of the other way around, it would currently be chepaer to take a train from London to Dover and do the 10 night cruise than to fly from London to Copenhagen and do the 7 night cruise). However, I have a feeling that if there is a late July Dover to Copenhagen repositioning cruise, it will be much more expensive than this year's mid-August Copenhagen to Dover cruise.