I do agree with all your points, they are flaws I see in the system, too.

However, there is nothing to be gained by any systemic changes in the US system until and unless your near-unique two-party system is also dismantled. Once other parties have a presence in the legislature, there is less need for a government to curry favour with the official opposition in order to get things passed, as the appreach can be made to smaller parties with less danger of having to accept 'wrecking' amendments to legislation.