To be honest; my experience was identical. 
I did the export thing for the flows (with the ALT button in the menu), and made screenshots. It was pretty easy to recreate and review everything. Added new insights to old flows. The main reason why I accepted this, is because with SHS everything is lightning fast. But, maybe this is different for others, because like you, I came from Homey 2016 to Homey-SHS.
Still have issue with some things, but I would still recommend people using Homey-SHS.
That said; it should have had a migration option.
