While addressing backshifting of epistemic 'would' over on English Language Learners, I ended up trying to analyse will/would usage in the context of...
1: Considering how long it's been out of the fridge, I think the fish will be putrid
2: ? Considering how long it's been out of the fridge, I think the fish would be putrid
...which I contrasted with...
3: Considering how long it's been out of the fridge, I think the fish will be unsafe to eat
4: Considering how long it's been out of the fridge, I think the fish would be unsafe to eat
It's my opinion that #2 above doesn't really work, because the fish either is or isn't putrid (and in most credible contexts, we're definitely about to find out soon, one way or the other).
By the same token, both #3 and #4 work for me, because we may or may not eat it - which uncertainty licenses the hypothetical, irrealis "not present tense" auxiliary verb form would.
But my reasoning came unstuck when I tried replacing think with hope...
5: Considering how much it cost, I hope it will be good
6: * Considering how much it cost, I hope it would be good (completely unacceptable)
I want to know if there's any justification for my not liking #2 above - and if so, why exactly?