I do play dusa and do enjoy her.
And that's cool but you're talking to someone who mains her. I doubt you play her as much as I do. Lots of games, lots of different builds, lots of observations made. Understand that you're talking to people who've done it all. A lot.
Sometimes I get the snake, but I skip it more than I get it.
And you're being told by multiple people that you should change that. Don't be hard-headed. Your recommended build leads me to believe you don't play Dusa much at all or haven't since 6.82...and that's fine but you need to be honest about that. Her skills have changed, their pros and cons have changed, and the meta has changed. It's time to update your understanding of the early game for this hero. Snake is great against 1 or 2, not just for the damage but for the mana recovery and thus effective HP, as has been discussed.
It's not even a debate; it's just a matter of how much conversation we're going to have to have before you accept your skilling approach is currently a sub-optimal build with her recent buffs and to open up to builds that work
best for her in 2015. It's not about
what can work; it's about what works
best for her. Skipping Snake is no longer a desirable build for all the reasons already discussed.