Wouldn't a full node use nearly the same space for large or small block sizes? I keep hearing that a larger block size for Bitcoin increases the network weight for full nodes, i.e. more hard drive space required for full nodes. 
 And hence it would make less full nodes, and so the network then becomes more centralized.

...but blocks are composed of transactions. And there'd be the same amount of transactions (more or less) either way.  And a full node needs to have all blocks.

Small block sizes:
Full node would download more small blocks.

Large block sizes:
Full node would download less blocks, but they are bigger.

Wouldn't they each take close to the same amount of space either way?
Yet this seems to be the main argument, other than the problems of forking at all for any change, against why not use a bigger block size.
I think the logical issue with that argument is the assumption that larger block sizes = less # of blocks. More likely, the number of blocks would stay the same (a block is "mined" into the blockchain about once every 10 minutes). Thus, the capacity of the blockchain would increase. 

Only if you assume that the number of transactions currently being "saved" into the blockchain is the upper level of the demand for such transactions would the storage size not be affected by larger block sizes.