The German light tank branch is the worst one in the tech tree, because it features very unremarkable vehicles. So, in order to make them somewhat fun and/or competitive, I would suggest giving them autoreloading guns.
Starting at tier VII, the SP I C will have a 2 shot autoreloader and 220 average damage per shot;
HWK 12 will have 3 shots with 240 damage each;
RU 251 will have 3 shots and 280 damage per shot;
And finally, the Rheinmetal Panzerwagen will also have 3 shots, but with 320 damage this time.
I heard the tier VII light tank here used to have an autoloader, so it would be cool to bring that feature back in an updated form. Also, I upscaled the RU 251's alpha damage, other tanks retained their original parameters.
Now, instead of being completely handicapped, the German light tanks would have a special little feature, making them unique. In my opinion, these changes would reshape the play style of these vehicles for the better. Feel free to discuss this topic.