In the slime tree, there are way too many slimes, so leveling up Slash Blast is not that bad. Also, we noticed that when we were training our Warrior, potions seemed to be better than sitting around and waiting. In other words, not maxing HP Recovery is a completely valid choice to us. One thing though is that instead of putting your 6 skill points from levels 29 and 30, he puts things into Endure. But your also able to put it into HP recovery and incerease the amount you recover, since Endure envolves you hanging from a ladder taking even more time to heal.
Final Thoughts with a Warrior Build in Maplestory: We truly do not care what you do with your Warrior as long as you.
1. Max out Improving Max HP Increase first.
2. Max out Power strike.
3. Do not put anything into Iron Body, because you get Hyper Body as a Spearman which raises HP(Maple Story Meso) by 60%.
If you want to max Slash Blast and level(Maplestory powerleveling) it a little earlier, and do not want to max HP Recovery like Richard Dong said, that is fine as well. Since your really only toying around with 4 skills, there is not much more to do with the Warrior.