I don't have a problem with wonders being the only means to generate great people. It merely bugs me that generating shepherds or elite archers delays my ability to generate great people.
As for the bug with cannibalism, I would recommend you change the "level up" mechanic you have for the city plot. This mechanic is identical in every way to the +1 per X pop already in place. How about every city gets a free building on founding (the "Cornerstone") that provides a per-pop bonus to production, food, and gold of 15 or 14. Thus, for every ~6-7 population, it's a +1 bonus to each. This way you can still keep cannibalism and similar mechanics in as they were. This isn't quite the same as +1 per 7, but it should be plenty.
I'd be careful about adjusting the food required per pop to 1. I did that way back in the days of SMAC and it got kinda silly.
If you want cities to grow faster, try adjusting the formula used for food-required-for-next-population. As I understand the formula is relatively steep, making growing past 15 fairly slow. As it stands, growth follows a progression of rapid expansion as more and more food tiles can be worked and are improved, but once those tiles are fully improved and all are worked, growth is being cut from two ends by a polynomial function AND from a reduced food income at the same time. I'm fairly certain the linear function of past Civ games was just fine given how the amount of surplus food also decreased at the same time.