Great idea, although it is quite inconvenient that you have to tap/swipe to show the modern version (at least on mobile). Makes it difficult to compare.
>In German you need to have that noun info upfront, otherwise you might not get the grammar correct!
In reality, (1) people rarely change their mind about what noun they're going to use such that the gender is different, and (2) when it needs to be done, speakers of German either ignore it or just go back and repair what they said, changing the forms of the determiner and adjective. Germans speak with no more planning than English speakers.
One might say the same thing about certain English grammatical phenomena. When asking a question, you have to consider whether the subject is going to be singular or plural: Is/are the dog/dogs hungry? This isn't needed in languages without subject-verb agreement, such as Swedish. But it makes very little difference to native speakers.