I have the feeling that this system is getting way too heteroclite : you have the usual Sony lenses, like the 28-70mm zoom, you have the Sony Zeiss lenses, like the 55mm and 24-70mm, you have the Sony G lens like the 70-200mm, then the two Zeiss Loxia and now the two Zeiss Batis. None of these lines is offering a complete line of focal lengths whether in primes or zooms. Yes, the system is still building up. But there could have been a better coordination between Sony and Zeiss (the Loxia were repeating already available focals). Now that was done, Zeiss could have finished the Loxia line instead of starting a new one. Or they should have started with the two 25mm and 85mm of the Batis line instead of repeating the 35mm and 50mm we already had with the Loxia line.
Further, they don't even announce their roadmap, so you don't know what will come next in the line that interest you most, increasing the difficulty of an informed choice. In the end, the best strategy looks like waiting.