A good move for him , Neil Critchley at Blackpool is a decent coach despite his RS background, so he’ll know Simms well. Mid table League1 is about right. I like Simms but he’s still very much a work in progress, far from PL ready , would likely struggle to get starts in a decent Championship side .
I think he’ll likely do well at Blackpool , if so maybe he becomes Championship loan next season still only 20 then. The worry , as others have mentioned, is that his contract is up end of June. We’ve been bitten by giving too long contracts to youngsters in the past but I think he’s worth a two year contract and accept he’s a slow burner , see what comes of it.