As a non-Japanese citizen, I know I have no say on when Japan opens. I am perfectly happy though making guesses. Japan doesn't have to follow what other countries in Asia are doing any more than the US, Canada and Mexico need to agree on all procedures however....
South Korea is letting in tourists. I've seen a mix on quarantine requirements, but going by the South Korean embassy in the US, it is currently 7 days.
https://overseas.mofa.go.kr/us-en/brd/m_4500/view.do?seq=761027&page=1 It looks like you mostly need to test before you go and test and quarantine on arrival.
Vietnam is letting in tourists on March 15. For US travelers, we will need to get a visa like pre-pandemic. For vaccinated travelers, they will need to test before entry, test on arrival and quarantine until the test results are received, ~ 1 day.
Starting today (March 7) Taiwan is going to allow business travel again. There are currently no visa exemptions.
Thailand has a Test and Go Program for Fully vaccinated travelers:
https://www.thaiembassy.com/travel-to-thailand/test-and-go-thailand-qu... It really doesn't seem like it's that hard and the website is set up to try to make it as easy as possible. They want tourists back.
The rest of Indonesia is closed to US tourists, but Bali just reopened along with its visa on arrival program. Bali seems to require proof of vaccination and a negative test upon arrival.
Singapore seems to be pretty similar to a lot of places for fully vaccinated travelers and requires some testing, registering your vaccination with a specific program, and having enough insurance.
I have not seen anything on Malaysia yet.
As of 2/10, the Philippines are open to fully vaccinated tourists from visa-free countries including the US. Visitors must submit proof of vaccination and get tested 48 hours before their flight, as well as self monitor while in the Philippines.
I don't know if I have a high bar for paperwork, but none of the requirements for any of the Asian countries listed above except South Korea with its 7 day quarantine, seem particularly onerous or all that much more than I had to do when traveling from the US Mainland to Hawaii. The Safe Travels Hawaii program is set to end March 25th, but I went to Hawaii in April 2021 and just got back from a second trip in February 2022. I needed to create and fill out a Safe Travel itinerary for my trips to Hawaii. For my April trip, all 3 of us needed to be Covid tested 48 hours before our flight. We also needed to fill out an affirmation every day that we had no Covid symptoms. For our February trip, we just had to upload our vaccination cards since all 3 of us are vaccinated and my husband and I are boostered. We didn't get our QR codes in time, so we had to wait in line at the airport to have inspectors check our vaccination cards. It really wasn't a big deal.