The chart does not sit right with me. It is difficult to predict what improvements will appeal to buyers, because all people are different. Most of these charts strike me as designed to rationalize spending, and perhaps over-spending, on a house.
In general, keep your home clean and in good order, de-clutter it and spruce it up a bit when selling (have it professionally cleaned, painted, etc.) and unless the market is really bad you will get a fair price, accounting for the market at the time, and how much interest there is in the house.
Final thought is that a house is an investment only in the sense that there will be some appreciation (particularly given the restrictions on new housing), there are tax benefits, and sometimes you get lucky and buy in a hot area and do very well. But a home also has significant maintenance costs, sales and refinancings have high transaction costs, and real estate generally is somewhat illiquid in good times (cannot sell and close in less than 30 days most of the time) and can be really illiquid in bad times (2009-2012 or so). As a result, the average person would be far better off ensuring that he or she is not house poor and has adequate income to be able to regularly invest in a diversified portfolio of stocks in a retirement vehicle like an IRA or 401K. In my opinion, that is a much better way to build liquid wealth than relying on a primary residence as a retirement plan as well.