Don't worry. We're working on preserving the old board "tree" (aka, "threaded") style. We're part way there already (see "display mode" and switch to "threaded"), but our intention and goal is to make it so that the threaded mode looks and behaves just like the "old school".

BTW: the reason for the change is not because we prefer the new form over the old (although many, many people do and haven't hesitated to tell us so over the years), but because we needed to change to a system that worked more efficiently on the server.