I would like the canvas UI to tell me if a transformer being used is a Blocking Transformer (or has blocking/feature holding tendencies), Red always blocking, or Pink when transformers have GroupBy tendencies which can be or have been enabled (change Pink to Red when in blocking mode).
The visual queue will tell me where I may have to control my flow of feature and runtime orders; or when I am about to create a loop which will trigger a linked transformer.
Added benefit it will visually tell me of aggregation points of data, and likely memory intensive operations, in my script.