Designer in Visual Studio
The azure portal designer feels limited in functionality and can only handle simpler pipeline scenarios before becoming unusable.
I think the portal should be for simple scenarios and the VS designer for the real world, source controlled and complex scenarios.
Released as part of General Availability announcement – http://aka.ms/logicapps-visualstudio
Ben Hatton commented
While VS has support for ARM templates, it doesn't know anything about the functions and object models available within the workflow.
Keeping ARM template schema up to date would be a good start, but some simple autocompletion and workflow definition validations (beyond json schema) would go a long way here.
Manuel Ramm commented
btw here are already some comments about this suggestion: