The value I see in this gun is that it has the quicker action of the Glock 19 slide, combined with the extra grip afforded by the full grip. This could turn out to be one of the most controllable 9mm out there. There are a lot of people that are quicker and more accurate with their 19 than they are with their 17, so in that sense, this will add to that in a positive manner. Maybe. It also has higher capacity of course which is a moot point due to the fact that the same can be achieved by using a 17 mag in your 19. It also looks as though this may come stock with non-plastic sights.
There are so many that say "It's not revolutionary" or "Glock needs to be innovative" and it is all a load of crap. Exactly how is a gun manufacturer supposed to be innovative in this day and age? Nearly everything that can be done, has been done in some form or another by the multitude of handgun manufacturers out there and if Glock does anything remotely similar to what anyone else has done, the internet warriors will then complain that Glock is copying others.
Glock just came out with their 5th Gen guns and everyone is whining about it just being a tiny change yet how many other manufacturers can say they just changed their rifling and barrels that they have used since the 1980's? Glock made their new gun arguably more accurate and more reliable and people say they did essentially nothing. They went away from the finger grooves showing that they were responsive to those whose hands the grooves did not fit. So, in summary, they made the gun more accurate, more reliable and made it fit more hands while offering three different factory sight options and people still whine about it not being enough! if that does not make people happy, what possible revolutionary change could they make to make the haters less hateful? Maybe they could stamp "SLIDE ZONE" on the slide or something.