I think you should ask yourself what is your long term plans first. By long term, i mean 10, 15 and 20 years and beyond. If you are planning to stay in the house long term or even take is as your retirement house, then you shouldn't be asking about the resale value and instead focus on what to do up for the house to ensure you don't encounter big issues in future.
Since your house was built somewhere in the 1990s, It would be close to 30 years now even though the previous owner did A&A 10 years ago. Even if you throw in 1.5M to do a reconstruction, I don't think this 1.5M will add on to the current valuation even if you decide to sell the house in the near future (within next 5 years). So if you don't have long terms plans to stay there, spending so much money to do up the house may not be worth it unless there is a huge spike in landed house prices again. We've seen landed houses prices jump more than 50% over the period of 2009 to 2013 and it is unlikely to happen again in the near future even though the prices will increase due to inflation, etc. Do also note that if you need to take a construction loan to finance the reconstruction, the interest rates for bridging loan (until you receive TOP) is much higher than mortgage loan and it will increase again soon due to USA increasing their rates.
My view is that if there's no major structural issues with the house and you are ok with the layouts of the rooms, etc, then just do a renovation as opposed to a full reconstruction if you are not planning to stay long term.