I'm not sure I accept your premises? I could certainly be wrong, but I have not gotten the impression that comments can be prevented by low karma, only posts to Discussion or Main. (And I recall the minimum as 20, not 2.*) The most obvious way to get the karma needed to post is by commenting on existing posts (including open threads and welcome threads), and new users with zero initial karma regularly do this without any apparent difficulty, so unless I'm missing something, I don't think it's a problem?
*ETA: It seems that 2 is the minimum for Discussion, while 20 is the minimum for Main.
Created throwaway, couldn't comment.
(So as to not propagate throwaways testing this, account is less_than_2, and the password is 123456)
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.