That is the way I would go. The Dark Eye and WFRP have similare themes including intrigue, religious tensions, political infighting and the struggle against nameless, covert enemies. Like WFRP, sometimes there is a big event (and sometimes the covert enemies are not so covert for a while) but they never are as gonzo as in TDE. Equally, the setting is never as miserable as WFRP. Personally, I like both settings but they scratch slightly itches.Isn't there a pure setting book, the Aventuria Almanac, that covers the whole continent? I don't know exactly what "the trademark TDE level of detail", but I'm not certain I need it to run a game.
If you want a complete overview of the continent, the Aventuria Almanach is available and I believe it's pretty good. If you want a detailed region to start with, The Warring Kingdoms details two kingdoms squeezed between the Orc plateau, the barbarian-viking Thorwalians and the Empire. They have been at each others throats for centuries (the book explains why) and offers intrigue, religious tensions and political infighting at a regional level.
EDIT: sorry, forgot to mention two things.
First, if the level of details found in the Almanach is enough, you might want to choose the Empire as your base. Again, similar themes with the Sigmarite Empire. You can draw some similarities between the two worlds but nothing is the same. Bornland is not Kislev.
Second, the other obvious path is to use the Old World and tone down what you dislike. I personally ignore all the gonzo stuff coming from WFB.