I agree with almost everything you say. There is one argument however that I dont understand. You say:
"What's concerning is the amount of nodes that will be running with an 8MB block size after a while. The blockchain will become substantially bigger than Bitcoin's. Proponents of Bitcoin Cash and big blocks claim this is not an issue because storage space is cheap."
Currently the blocks created on the BCC chain are much smaller than the blocks created on the BTC chain. The block are all well below 1MB because the number of transactions is relatively low. The BTC chain is now growing much faster than the BCC chain. It seems to me that the number of nodes supporting BCC is indeed a concern but not because the size of the blockchain is too big.
You're right. It's definitely not a concern right now, but it could be in the future if it gets more transactions. This will largely depend on its development and how things unfold with SegWit2X, as well as general future cryptocurrency adoption overall. Ultimately, the blockchain size of BCC should exceed that of BTC, which will implement the Lightning Network.
I will edit that statement, thanks!