How many of those lines are logging by default? I've worked on a system very much like what you describe - just booting it up would cause over 20MB of logs to be written if logging was cranked way up, but even debugging we didn't turn it all the way up for all modules. By default it would log when a module of code was entered, and major system events. It was great for debugging since QA could just attach a log to a ticket, and even if it wasn't reproducible you could see what was going on when the problem happened. If you have serious multithreading going on then logging is still better than any IDE or debugger I've worked with.
