Unless I've missed something in Spartacus, it seems there is only one plugin available to manage display of comments on the sidebar. Please let me know if I've missed something...
I'm thinking of extending the current Comments plugin to support aggregation (option 1) and threading (option 2) of comments.
Basic aggregation would be simple - just display the last comment for any given post up to the maximum number of comments defined. The purpose is to illustrate comment activity across the blog instead of a string of comments that are relative to one post only.
A more advanced aggregation could display the last comment for any given post where the comment submitter does not equal the author. This has advantages and disadvantages in that it gets rid of the trite closing comments ("Thanks, have a nice day"), but might look like a comment submitter was left hanging with an open question, which makes the author look un-involved and irresponsible.
A super-advanced option would include comment-management in the Admin > Comments area where each comment could be flagged for display, or not, on an entry-by-entry basis. This may be a bigger pain than most folks would ever care to deal with, but it gives very granular control over what gets displayed on the home page.
Threading could be as simple as showing the last comment on any given post (up to the max comment limit) and displaying some configurable number of related comments inset a few spaces. The purpose here is simply to organize the comment string so that it is easy to distinguish from one topic to the next.
More advanced comment threading could include use of a tree model where the last comment on each post is displayed (up to the limit) and an expand/collapse button reveals some number of related comments for the particular post.
These are just some initial thoughts - any feedback, would this be a worthwhile project??
Adam