He has only been inactive for 4 days which doesn't count in my mind. The map is still his original work and it can't simply be copied or outright stolen.
dakoish, safe yourself a major hassle and try to contact the mapmaker to get his approval for what you intend to do. If that doesn't work the contact Fizzer and ask his advice on the situation. The last thing you want to do is put all the effort into revamping the map only to be told it can't go public due to it's similarity to an existing map.
Francisco, the problem is in remaking the map. If you are planninng on using the same or very similar territories then you are essentially infringing on copyright. You are essentially stealing someone else's intellectual property.
The many world maps all have their unique qualities that separate them from the others and make each unique. A remake (as I look at the term) would not be unique.
But the maker of that map, is not the inventor of the original map. The territories are taken from a game-map, if I remember correctly. What the original mapper did, was add bonuses and redrew it on inkscape, and it these two things which are needed to be remade anyway.
I don't pretend to know exactly how the original map was laid out but I would highly wager that some aspects of that map are original creations. As such, those original aspects are intellectual property.
As I said above, the best option is to check with Fizzer to determine whether such a remake would be acceptable. Would safe the guy a hell of a lot of work that could be wasted.
To my knowledge, you can do anything as an adoptive owner. However, maps are only given out for adoption at the owner's request or if the original mapmaker is long inactive. Four days is not long inactive.
A remake of the map I edited wouldn't necessarily be called Europa Barbarorum then, if you edited the original states. The only things I added, to be honest, were Ethiopia, India, Siberia, and some minor changes here and there. You can make a map based off of mine, but it might have to be re-titled, all of the territories re-outlined, and maybe even expand or shrink it to see your needs.
Just know that when I added the new eastern territories, I tried my best to make the territory names as historically accurate as possible, similar to the original EB map. If you can do the same, I would appreciate it.