BRC-20 transaction patterns could be identified regardless of their size, so a complete "block" is technically possible,
Of course, but BRC-20 folks could simply change the protocol, or change directly to a competing token format, like Casey's proposed "Runes", or even old ones like coloured coins, Omni and Counterparty. As long as the token creator is still around, he can simply swap them for the new format (they're essentially centralized). It would simply lead to an arms race and in the end nothing would have been improved. So I strongly oppose Luke's approach, even if I won't win a popularity contest in this thread with this stance 
My opinion is that the only effective strategy against the BRC-20 spam is pointing out, in all communities, that BRC-20 tokens are probably the most useless (and thus, worthless in the long term) assets ever created. These days this may seem different, but I don't give them much life after this bounce. Those who buy at current prices into tokens like ORDI are ... well, at least going for an extreme risk.
(Fun fact: after the success of ORDI, a token called NALS was created and is doing quite well. That shows very well the value proposition of BRC-20 tokens.
)Reading into Luke's comments here and there regarding this "ban" he does refer to it as "spam filtration" and he seems to be counting on the fact that most people including miners would activate the change, I find it very hard to believe that mining pools will opt-in for a new upgrade that makes them lose proft.
Here I agree.