The whole argument against Germany's overlap with other civs is that it is fundamentally bland. Germany's UA changes little, if anything, the way you play the civ, unlike other UA's that are really game-changing (sometimes in a quite literal fashion, a la Venice). That being said, If I were to dredesign Germany....
Germany
UA - Mittlestand
Land trade routes yields science equivalent to 25% of their gold, grants + 5 production if the city being connected has a factory present on it
UI - National science library (replaces landsketch)
It can be built by great scientists, engineers and merchants
+4 science, +1 culture, +1 culture with each passing era
It also yields +3 production if it is traversed by a trade route
UU- Panzer (remade)
In addition to the previous Panzer stats, panzers will start with the following promotion
Auftragstaktik: If this unit kills an enemy unit, it gains HP and one additional attack.
Comment:
Germany has been fully remade into a flavourful civilization which tries to make synnergies between Germany's most known 3 strenghts (science, industry and commerce), with an added dash of late era warfare too for a full representation of this complex civ.
Its UA gives a much needed boost to land trade routes while giving Germany a scientific edge and a more late era push as well (production bonus upon the arrival of factories). In addition to that, its UI, the National science library, aims to create synergies with its UA: it will also help you out with your science output, and you will need land trade routes to fully unlock the potential of this improvement (production bonuses). Note as well how this UI can only be built by great scientists, engineers and merchant, thus making Germany quite fond of the world congress "funding of sciences" resolution as well
Finally, The panzer has also been upgraded in order to compensate for its late game status, and in way for it to be synergistic with the Blitkrieg ideological tennant, thus creating a distinct enough civ (I think), which becomes stronger the latter the game progreses, but that it is distinct enough to notice an early difference when playing it.