I like this one quite a bit. Shirou does seem to be becoming a bit too powerful. However, at the same time, while the current Shirou in the story may have easily won the canon HGW, Third Fang has introduced a ton of other elements into the story, such as Shirou's existence being revealed to the world, and him being recruited into the Clock Tower as one of Lorelei's subordinates, while at the same time being forced to hide his partial transformation into a Dead Apostle.
Overall, it seems that the Fifth Grail War in this universe is going to resemble the Fourth War
much more than the canon Fifth War did, which means, above all other things, that nothing
is going to go according to plan, and that the war is not going to be a cakewalk for our protagonist.