The new arrays sound like a good upgrade. The link you provided states the new arrays will produce 30% more power than the existing arrays that were installed in 1993. I suppose that will take it back to something in the neighborhood of the 1993 power levels. Solar arrays degrade in space due to radiation effects. I don't know the numbers in LEO but the geosynch birds I used to operate lost about 3% of their electrical power each year due to degradation.

I like that the new arrays will restore the power to the prior levels (or perhaps a bit higher). This will provide more power to operate the instruments, making Hubble operations more efficient.

I really like the fact that the new arrays are smaller, which will reduce drag effects. In addition to reducing the need for reboosts which have to be done by a Shuttle because the Hubble has no propulsion system, it's possible the smaller arrays will generate fewer vibrations, making for better long-term exposures.

While the article didn't say so, it wouldn't surprise me if the new arrays are made of something like Gallium-Arsenide cells instead of the old silicon technology. Not only is GaAs more efficient than silicon, it tends to degrade more slowly when exposed to radiation.