When you use Redline Smalltalk you don't lose anything that you are used to with the Java ecosystem. You can reuse all your existing Java classes from Redline Smalltalk, make JARs, debug with breakpoints and step line by line through Smalltalk code (inc: in and out of Java code). The classes you create with Redline are callable from Java, they are proper classes full of bytecode. Redline Smalltalk itself is written in Java so you will understand its source and implementation if needed. We are paying close attention to ensure Redline Smalltalk works with popular toolchains and doesn't present barriers to their use.
There is one downside, you will need to adjust to typing a lot less and using a more dynamic environment which means a far smaller development cycle with quicker feedback.