The US tax system - what difference could reform really make to the market?

Some US market sectors that would be major beneficiaries from tax reform haven't seen marked investor interest. What about if tax reform actually occurred?

Tax reform is one of the Trump presidency's core policy planks. However, Paul Moore suggests in this 5 minute video that the stock prices of companies likely to most benefit from tax changes have not markedly outperformed the rest of the market. 

Although there's a long way to go, Paul suggests some companies could get a significant boost from tax changes.