> It ISN'T low right now...
I agree, but I don't think it's a good idea to softfork it to lower than 4M WU though, and I don't think we need to;
hopefully when exchanges start using Lightning or Liquid, avg blocksize will go down.
> Extension blocks are not softforks, and are unreasonably convoluted for no
real gain. When the time comes, the block size should be increased only using
a hardfork.
It depends on how you define soft and hardforks, I suspect you don't see extension blocks as a softforks because old nodes won't maintain a correct UTXO set.
I think an extension block is a softfork because old nodes will still be able to follow the mainchain.
I don't know if a blocksize increase hardfork will get consensus as the idea has been ruined by all malicious hijack attempts we've seen over the years.
Hampus