If you haven't already, it is crutial to adapt the DTE tables to the german language, so that your script is reduced in size. If such a thing is possible, it would be be possible to hack the DTE decompression algorithm to support recursivity. My own experience has proven that a text usually compress to 60% of it's size if only normal DTE is used, but can compress down to 30% of it's size if DTE-within a DTE is allowed.
For example you could have "di", "e ", and then have the 4-letter sequence "die " take only one byte instead of 4, resulting in very significant space savings for the game's script.
Another trick is that you could use the same data for "Kaufen" and "Verkaufen" by tricking the pointers
| +--------- Pointer 2
+------------ Pointer 1
Of course we have a problem with the casing, so only do this if you really are short of room.
But as Disch said, if you're not happy with how it looks, you could take a look at other games to see if there's a font you may like. Or create your own, even.
If the font should be changed I'd suggest using the regular Squaresoft fond they used in FF4 (SNES) and all other SNES and Gameboy-area games they translated in english, that font was slightly improved in the FF3 (NES) english translation.
Before the german defeat in the great war in 1918 the german language was exclusively written using gothic letters that looks super cool but are super annoying to read, you could try to do add this in option if you feel funky.