my opinion is that people should stop fighting in a thread and fight in a PM.
now on with the real topic.
Will love help Harry in defeating Voldemort?.
Yeah, in some way shape or form, the sacrificial protection given to Harry by his mother helps him love because it lets Harry know that there is good in the world. This also lets Harry 'love' people even though in the case of Wormtail he didnt kill him, this goes the same for Snape.
Yes i have brought Snape into this, in my opinion Harry will protect Snape in some way, and not kill Snape. This is again due to Harrys ability to love.
So in my conclusion, Harrys ability to love will help him.