Bugs aside, I don't think the number of logged entries should have dramatically increased, as in general Moodle HQ have mainly just converted existing log calls to use the new system rather than adding new logging.
By the way, at the OU we will be setting our systems to use the legacy log table because we have a number of integrations with third-party systems that depend on it. (Obviously we'll turn standard logging off.) If you're having problems with the new log table, you could also consider switching to legacy logging for the time being?
Most likely we won't change to use the new log system until we have selected or implemented a log output plugin that doesn't use the database. There's actually a great opportunity for performance gain compared to 2.6 and previous versions, if you log somewhere that's quick to write to and doesn't limit scalability in the way database writes do, e.g. the local filesystem. I'm not sure if there are any high-performance log plugins available out-of-the-box though.
--sam