Log4j opted for a more conservative solution to their original problem and the day later, many folks need to go through the whole process again. I actually appreciate this project's approach. 

One suggestion I wanted to make: could maybe reinstate the removed functionalities take place in a separate artifact, i.e. I doubt the majority of users need JNDI code at all. Those who do need it could then just add logback-jndi to their classpath (same for JDBC, SMTP, etc.).