Especially if they want to keep parts like Splitter and Joiner and just copy them over. I just ran into too many libraries that copied Guava into their own name

Especially if they want to keep parts like Splitter and Joiner and just copy them over. I just ran into too many libraries that copied Guava into their own namespace and now your project depends on x different copies of Guava indirectly. Besides that I find it strange to get rid of ImmutableList as I don't see any usable alternative. I also find the newXXX methods very helpful and much more readable (e.g. Maps#newHashMapWithExpectedSize) and preferable over constructor usage even with the diamond operator as it also allows you to change the implementation afterwards.