It's really not worth commenting in general on Trump's foolish and frivolous new tax "plan," but here are two quick takeaways about the issues associated with two features.
First, he appears to have adopted a version of one of the stupidest ideas to emerge in tax policy for many decades - the idea, from Sam Brownback's calamitous Kansas tax "reform," that a low business tax rate should extend to all business income, such as partnerships, even with no second level of tax a la the current corporate income tax. The Kansas plan, which exempts such income from the state income tax, means that, say, in a law firm the secretaries, paralegals, and associates are taxed on their labor income, but the partners are not taxed on their labor income. At the time, even some people far more sanguine than I am about the Ryan-style tax cut playbook pointed out that this was idiotic, and events have confirmed this. It's not only upside down taxation, like the pre-French Revolution system of exempting nobles from general taxation, but distorts real activity and encourages pointless tax planning games. Trump would adopt this thoroughly discredited idea, albeit with a 15% (in lieu of 33%) rate and extending it to sole proprietors. So now the idea is: At all costs, don't ever be an employee! Makes a lot of sense.
Second, on a more favorable note, there is something or other about people who work getting to deduct childcare costs, perhaps based on an average measure of some kind rather than based on actual costs incurred. While this can be validly criticized on some grounds - e.g., no effect if you're too low-income to owe tax, and should the benefit be tied to your marginal tax rate - there are also arguments in favor - e.g., in some settings childcare expense really is a marginal cost of deciding to work. So the issue merits further discussion and debate, albeit perhaps not in the context of the current U.S. Presidential campaign (where there are bigger fish to fry, such as whether the rule of law will survive).