I don't like the era requirement for wonders. We'll experience beelining all the time, just to get to the next set of wonders. I assume we players wouldn't actually slack off getting the right amount of SP's to make this possible. The era-scaling bonuses from a myriad of sources are already enough of an incentive for this. I find the early eras very short-lived as it is.
Also, how would the wonders in the tech tree look like? Will their icons still be show on techs in their corresponding eras, or will there be a sub-panel which shows all wonders unlocked in which eras? The former would be hideously unaesthetic and inconvenient for new players.
I thought the idea of introducing the SP requirement for wonders was to prevent the tech leader from hogging all the wonders? Players with disproportionate tech levels relative to their culture should have to wait a bit until they meet the policy requirements. Players who have a good balance of tech and culture should still have access to the wonders by the time they reach its tech requirement. And culturally sophisticated ones will get the finisher wonders faster.
Roughly correct, though if you have the proper amount of Social Policies the wonder will become available even if you lack the techs (and vice-versa). So tech leaders still have a viable wonder strategy, though they'll lose out to many Social Policy wonders and perhaps ideology wonders as well.
G