I really doubt Odin was hitting Thanos with everything he had. This was near to Asgard remember and Odin wouldn't be fighting Thanos on the same level he would fight Surtur or a Celestial for example. Nowhere was it said Thanos was a match for Odin here, just that he was a lot tougher than Odin had bargained for.... think of when Thanos faced down Galactus for a good idea what i'm getting at.
| > But how come Odin wasn't able to summon that type of power when he fought Thanos? Odin's more powerful. |
Even Death has her limits. Death is not the only force out there, there is such a thing as fate.
| > I know Drax was glowing with a green energy, but Death is more powerful than Kronos and could easily overrule any bio-design to kill him. She was starting to express love for Thanos, so I don't fully agree with this idea that only Drax could have done what he did.|
Drax was pre-ordained to kill Thanos, even Death cannot rewrite destiny and i think the allusion here was that this was always how it was going to end for Thanos - that weariness of life from him was what was built up to over the course of Annihilation and he realised it was now time to go right there at the last moment as Death appeared to him....