Allow certain output ports to have their feature caching disabled to improve performance.
As an example, I quite often use the FeatureMerger. With Feature Caching turned on it will cache all the output ports, as described here under the 'Unconnected Output Ports' heading - https://knowledge.safe.com/articles/79739/feature-caching-and-performance.html - I often don't care about the UnusedSupplier and UsedSupplier, but they tend to be the largest datasets and add significant time on first run/uncached runs.
What would be ideal is an option to turn off the feature caching for certain output ports, perhaps under the right click menu of the output port itself.
Admittedly this right click menu only appears once the feature caching is done, but you get the idea.
This is similar to this proposal - https://knowledge.safe.com/content/idea/77431/feature-caching-woes-reuse-large-attributesturn-so.html - But a bit more granular, whereas that proposal suggests allowing feature caches to be turned off for entire transformers, this one proposes only turning them off for certain output ports.