Looking back on
Nisemonogatari, it seems that
Koyomi is really weak compared to all of the oddities he faces. Suruga's monkey form easily defeats him (even though his power was temporarily boosted). The snakes in Nadeko snake would have killed him had Kanbaru not intervened, he needed to be saved from Black Hanekawa by Shinobu. In the latest episode he would probably have died if Yozuru had decided to prolong the fight. This is in spite of him getting the largest power-up yet from Shinobu.
Considering that he once told his sisters that
The first requirement of being a hero is to be strong, and the they're fakes given their lack of strength, it seems odd that Koyomi is so underpowered compared to the oddities he faces.
Does he ever get stronger in later episodes or in the Light Novels?