No it wont be 128GB. Youd probably get away with a 32GB card but Im looking to the future. The thing is the Switch has 32 GB of memory with 8GB of that reserved for firmware. So theres only 24GB to store games.
2k could use the 32GB cartridge but I think they only used the 16GB cartridge for NBA 2K18 which meant Switch owners had to buy external memory to download the game. I think its gonna be the same situation for WWE.
I dont know why Nintendo always release consoles with a limited storage size. Well, the obvious reason would've been to release the Switch at a reasonable price but I dont think a 32GB console is practical in 2017.