I wonder how much Morgoth did fear Turgon & the power of Gondolin - His forces destroyed the city in less than a day. We have to keep in mind that, within ME, the accounts were written by his enemies, Elves & Men. Tolkien was well aware that all historical accounts are biased. Look at the stated facts, not the Elves' interpretations. If Morgoth was REALLY afraid of the power of Gondolin, he simply wouldn't have played with Hurin for so long. I suspect he was a lot more confident than is made out.
I don't think Morgoth had any plans for Hurin, or intentions for his fate before he was captured - how could he know he would be captured? I think he was probably surprised (& happy) that he got him, but his plans would have been formulated there & then. He was thinking on his feet. Hurin was a 'gift'. He decided on his course of action based in part on how Hurin behaved before him. If he'd been really desperate to get infomation from him, he'd have put Hurin through torture, broken his mind & got it.
Tragically, I don't think Morgoth saw Hurin as anything more than a proud upstart who needed breaking, & teaching to respect his 'betters'. The fact that he could also do more damage in a wider context would just have been seen as a bonus.
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