Does indy by default mean
1. only generate one set of groovy-* artifacts where any .groovy source files in the Groovy source itself are compiled using indy (no more separate indy jars)
2. continue to have two sets of artifacts where the indy set would go in lib/ by default and -noindy jars would exist that could replace them if old callsite code is desired
I took Russel's original suggestion to mean #1 and I would be in favor of that for 3.0. I think any performance concern would largely be confined to some of the sub-projects in the Groovy codebase since most of core is written in Java.
The other consideration in making indy default is whether indy will be enabled by default for compiling user supplied source and this is what I think most are referring to in the replies. This is where I agree that there is no rush to remove the callsite code and it would be good to have a --no-indy option for the next several major versions after that change is made.