Trials of the Foolhardy? Never ended up playing it as we didn’t have four (competent) players available then to open it, but it could be fun.
But in all honesty, as can be seen from the Dev Blog about translating the old maps the work put in that is almost as much as completely new ones. Basically, only some of the assets can be reused, and only the basic design is still there. Besides, while I was slightly disappointed that Wizard’s Tower wasn’t in BtU (it’s one of the most interesting map designs, after all), I can also see that its narrow corridors and labyrinthine design is problematic with the style of the newer game, making translating it even more troublesome than many others. Same goes for Drachenfels, too.
There’s an additional thing that some noted quite soon after Back to Ubersreik came out: While the old maps bring out some nostalgia, these are maps that many of us have run through and through, dozens if not hundreds of times each. The nostalgia disappears soon and we’re left with very familiar maps, even if there are a few new things to do and the books are in new locations. Of course, this doesn’t apply to new players, but I’d say quite a lot of us experienced players are veterans from VT1 already, and thus familiar with the maps.
For those reasons, I’d rather see completely new maps than rehash of the old ones, even if the old ones are very good.