When you need to tweak a node in the beginning or middle of node flow it's sometimes super slow and unresponsive because Substance Designer calculates evrything after. Diconnecting and re-connecting works but it makes so much exra troubles.
I'd love to see an option to pause evrything but only after a node in 2d preview currently with some "paused" indication in 3d preview . In fact I think it should be a default behavior.