I'd be ok with it, I even edited tvt's map just the same day he uploaded it ;) It really gave me some feeling :)
As of the credits, I'd only add an "edited by xyz", and a new version number, everything else would be too much imo.
You also should try to keep the style of the map, of course. The decoration methods, the colours and such.
Imo it would be a waste not to finish all those maps with great concepts in the DB.
i heard you go in hell when doing this.
you know, mapmaker's hell, where mosq is the (lemuria) devil, and where tankrange is 4times of normal range. uh, and there are no custom ramps at all, but every standard ramp you place is perverted and works as unpassable doodad and stuff...
and I heard the tanks get frog h4x and can shoot down mutas OH NOES
@spinesheath of course I'd keep the map mostly the same, only edit what is necessary, and maybe add one or two features of my map making styles, but it would be my edit not my map. And that's what I had planned to do for credits.