OK what about this. . . instead of being able to purchase, they make the Tier 1 ideologies cheaper than the Tier 2, etc. The thing that sucks is that you've unlocked a bunch already, a Tier 1 technology can cost like 60 points which sucks. Tier 1 should always cost like 20 or 30 at the most.
Well...
I think the idea is that Ideology is not like the Tech tree, which is a "collect them all" strategy. Rather, Ideology is about specialization and picking a path - that is, it's about depth, not breadth. They tried that with the choice techs (pick 1 of 3), but people really didn't like that, so we're back to Get 'Em 'All in tech.
Keeping Ideology so that you're NOT going to have breadth, but rather have narrow paths of abilities, I think is important to keep it distinct from the tech tree.