Name squatting — if creating a community is so cheap, why not squat the name of hundreds… thousands of online businesses?

This is not going to be a thing. @roadscape has mentioned it's just going to be a number ID that can be named.

Community Creation Spam — if I were to venture I guess, I would say that within 48 hours of the launch of communities, there will be well over 1,000 communities created by less than 100 people

Again this seems based on your first point being what you thought it was, it won't matter if your community is the first or 1000th to be created, what matters is if you can get it attention and if users will want to use it.

Waste of an Opportunity

of what? to burn more steem, to send steem to the dao? doesn't look like a lot of authors are doing this in general so why force it onto something like communities.

… unknown impacts of a low barrier to entry

Yeah, good one.

Don't have time to read the full post atm but just wanted to point that out when it seems most was based on your first point.