The Iowa Noxious Weed Law: If I were king

I recently had a discussion with a farmer regarding the Palmer problem, and he asked if I were 'King for a Day' how would I change Iowa's noxious weed law.  I came up with four suggestions regarding classifying weeds as noxious:

1)  Eliminate any weed from the list that is widely established in the state;
2)  Change the focus from weeds of ag fields to invasive plants that threaten natural areas;
3)  Remove the list of noxious weeds from the Iowa Code, and create a committee of experts that would be responsible for managing the list; and 
4)  Keep the list small.

My rationale:
1)  Including plants that are widely established in the state makes the law unenforceable due to limited resources.  Anytime I suggest this at a meeting someone always brings up Canada thistle.  I ask “Do you really think we would have more Canada thistle if it weren’t a noxious weed?”
2)  I can think of very few weeds (Palmer amaranth is one) that pose a greater threat to Iowa farmers than the weeds we already have.  There are agricultural weeds in other continents that pose a threat to Iowa (particularly parasitic weeds), but those are covered by the Federal Noxious Weed Law, and I see no need for redundancy.  In natural areas (prairies, forests, etc.) we expect the native plants to fend for themselves, so introduction of exotic species can have a huge impact on these ecosystems. Control tactics are required on an annual basis in agricultural fields, and these control tactics generally don’t care if a weed is native or introduced.
3)  Currently any change in the weed list needs to go through the legislature.  This is a very time consuming process, and it is hard to convince the legislature to make changes.
4)  Counties have limited, if any, resources to enforce the noxious weed law.  Keeping the list small will increase the likelihood that counties make efforts to enforce the law.