These arguments are too speculative. I'm not convinced that batched transactions can't scale the thing, and I'm not convinced that transaction fees will be too high, and I'm not convinced that there will be such a huge need for block space. Fees can go lower than 1 sat/vbyte. The blocks are probably already too big, IMO. It seems darn near perfect... Longer block intervals would be nice, but I don't see anyone raising that issue yet. Focus on the privacy issue - maximize the good that comes from the criticism. Imagine if we get this perfect scenario, where the institutions get so married to Bitcoin that they can't back out when we suddenly all start running a version that has getter privacy. Push for that...