Yes it was a bad deal . However Larsson played very well in year one and came with cap certainty for 4 years.
Saving cap dollars was part of the transaction . He has regressed which makes the deal terrible.
He had very limited offensive upside from the start. Hall was underpaid on his deal. He's definitely worth 2 1st rounders, or a blue chip prospect + 1st rounder. So, compared to what Chia should have gotten, and what he did get, I would be pretty upset if I was an Oilers fan.