Its been somewhat tested but I feel it could go either way due to the parsers not being super accurate but you can never really have too much of both. I would be leaning more towards saying BLM will benefit a lot more with +crit and SMN would probably be better off with +det even though DoTs can crit I wouldn't know how to argue that more base dmg would yield greater results over a small amount of crit chance without soft/hard caps.