Hey Andy,
We removed them because we feel that the syntax introduced in FactoryGirl 2 is the ideal solution; it requires no monkey-patching and works with all ORMs, not just ActiveRecord. There will be no replacement.
If you were using RSpec's described_class to piggyback off of the make syntax, we've changed build/create/build_stubbed/attributes_for to accept a class in addition to symbols to refer to the factory - this was done specifically to help during the removal of the alternate syntaxes:
https://github.com/thoughtbot/factory_girl/commit/f83c27e15d00beff864be32bf89c6beac33ae0df. This feature was released in 3.4.0, so if you want to rollback to the latest 3.x (3.6.1), you should be all set to convert these over gradually until you're ready to upgrade to 4.0.
Hopefully I covered everything; let me know if you have any more upgrade questions.
Best of luck,
- Josh