Whether this is good news depends on whether you believe this was just a temporary cyclical effect, in which case stronger growth in past years might just mean slower future growth, or whether you interpret the figures as suggesting that the long-term sustainable growth rate of the economy has increased.
There are two reasons why you might accept the second interpretation.
First, the change primarily reflects lower estimates of inflation in the economy as a whole. Second, the figures suggest growth was more balanced than previously thought, with less reliance on consumer spending and more on investment and net exports, which might make it more sustainable.
If you believe this more optimistic story, then it might reduce the need for increases in taxes and interest rates. But that is a big ‘if’ at this stage.