Most of these things really come down to implementation detail(e.g. formatting rules), and they are mostly interesting for aesthetic purposes.

The important ones like conventions surrounding replies are weird artifacts left over from the early days of the product. Twitter bottlenecks quickly in lengthy conversations amongst multiple parties and you really have to carefully respect the social dynamics it creates, or people will just block your rude self. If there is one place where the product could use revision, it's in improving average case conversation quality.