At start, every colony populated by a species produces POPULATION * INDUSTRY_PER_POP (default 0.2) * SPECIES_TRAIT (0.75/1.0/1.5/2.0/3.0).
Most bonuses you can get from researching techs are pop-based with values 0.1, 0.2... 0.5, and even bigger, IIRC. From those bonuses, some are applied before the species trait (so they are affected by it) and some are applied after the species trait (not affected), but that distinction isn't relevant here to me.
My point: you start with 0.2 as the basic production bonus (20% of population), and the smallest extra bonus you get is already +50% of that (+10% of population). That's a lot. Once you get a second bonus, you are already doubling initial production, or more if it was a +0.2pop bonus (so total +150%). This means that if you neglect production and your enemy doesn't, he will be producing several times more than you, and that is hard to overcome. Therefore, you never neglect production bonuses if you have colonies set to production, they are always prioritary over most other techs (only other techs that are as important are military and research, always circumstantially).
All the same goes for RESEARCH_PER_
I think it is better for steamrolling control to make the extra bonuses smaller in relation to the initial bonus. We could make initial production bigger (INDUSTRY_PER_POP = 0.5) so that a +0.1*pop bonus becomes a +20% over initial production.
I would expect from this that empires that rush production bonuses does not get as much advantage as they get currently. And the same for research.
Edit: this comes from my current work with the new tech tree, I'm with the research and production bonuses this days.