It's also possible that thrall lost his warrior-like skills because of a lack of practice as he mostly just uses his shaman powers since the WOW TBC Gold war ended using archimonde in Warcraft 3. So maybe thrall has grown weaker as a warrior during the time. He is now more warrior-like, and could probably kill makgora using an axe throw "for Azeroth!" Just like Helya.
Although Thrall killed Garrosh using his shamanistic skills but he still felt guilty about how he handled the situation and how Garrosh cheap Burning Crusade Classic Gold was killed due to Thrall's actions as well as all the other factors that contributed to his loss of power.