I actually like the current tech tree, at least the beginning part. By turn 100 or so, depending on how cramped my starting area is and how annoying monsters/AI is being, I generally have 'the basics' down (autolabs, basic factories, orbital farming, extra supply) and am well on my way to galactic domination.
I suppose it breaks down a bit after around turn 300 or so, when you're getting so much tech research that your biggest limitation are those techs that have a minimum number of turns. By then, you're getting three and four techs per turn and get loggerjammed by some of the longer techs before you can burst out into a new venue of research.
I also like the current tech tree. My only gripe actually isn't with the tree itself, but with the UI associated with it. Each time a tech is added to the research queue, it resets the tree view to the original position. This gets annoying when you're trying to queue up a half dozen or more techs.