I need your help. Which states can be governed by a simple majority? If the current US Senate rules are so great, you'd expect them to be replicated in lots of States right? And if any state does dare entrust its governance to the tyranny of the bi-cameral legislature, with their penchant for spending less on redistribution, well we should expect those states to be doing very poorly right, what with all the crazy laws and socialism they will have.
It turns out this is surprisingly hard to answer. The National Conference of State Legislatures produces items like this and this which highlight the complexity of this topic. I started out reading various State senate rules but states like California, with its two-thirds budget requirement mean that majority rule isn't as simple as the absence of a filibuster.
Inside I will try and lay out an approach to answer this.