If Bitcoin would not have been considered as an investment, but as a means of payment, maybe we would not have any taxes. But if it is taxed, it is also in the interest of governments to simplify the transfer not only of the citizen. The taxes don't care about good or bad news, there are here each day of the year. You are supposed to report the loss too, to be deductible (from the Income-tax, or another)
If you have a loss in your trading then there would be no tax to pay because the tax would be base on your income and since you have no income in a sense, then you have nothing to pay. However, there might still be a need to file the income tax though so that the tax authorities would not hunt you down when they learn that you didn't file.
As for the simplification of taxation, Japan sure is the fastest to advance when it comes to cryptocurrency and I hope that other countries would see Japan as a model for their cryptocurrency legalization and adoption as well in the future.