Yes, the U.S. should consider following in Japan's footsteps and move some public holidays to Monday. Three day weekends are a rare occurrence in the country, but public holidays that do happen to land on those times are often some of the most profitable times for business who stay open (in the case of sales and needs) and having more public holidays would only boost revenue. More importantly, it would allow the U.S.'s citizenry to enjoy more off-time with family and friends, as well as enjoy their own private time for an extra day.
Japan is in tune with the times in giving citizens Monday holidays, so that people can enjoy three day holidays. In Japan, this is a new thing. In the US, there are plenty of national Monday holidays already, such as Columbus Day, Day After Christmas Day, Memorial Day, and a number of religious observance days. In the US, there is a good mix of holidays on different days throughout the calendar year so people can enjoy a day off on a regular basis on a different day most every month. It means people will be less likely to take days off from work. In reality, the Monday holidays make the three day holiday time worth waiting for -- it's special this way. People look forward to these longer breaks and make appropriate preparations according to the specific time of year. Holidays on different days makes holidays in general more exciting. Just remember to have a calendar handy.
No, holidays should not all be moved to Monday. The date of the holiday often has a significant meaning. Moving it to a Monday takes the significance out of the holiday. Holidays aren't about convenience or getting the most out of the time off. It's about honoring and celebrating the purpose of the holiday.
I like the fact that Japan is taking care of their citizens in such a way like that. If the U.S government did that, I would be more content with our govt. But judging from the way things are in the U.S, it would take too much of an effort for all corporations and entities to modify their schedules to abide by the new laws. And sometimes, we just need a break in the middle of the week too.