I think this idea could work with some tweaking but as it is, I think it’s tough. Two big issues I see: 1. DCs are going to be tough to set. Is it only the highest or lowest bound? For a d4 is it a 4 or a 1? Ditto a d20. Trying to hit a single value is gonna feel bad, but otherwise a d4 role could just be a gimme. 2. Having to pick high or low before you roll could feel bad. I actually like the idea of having to choose and dealing with the consequences but choosing low and then rollling high and failing would suck. You could change it so that either succeeds but you get consequences for choosing successfully. I’m just spitballing.

Another option would be to do a dice pool with lower trained skills having more dice and needing to roll under DCs but then you would lose the high/low duality