Free stuff should only apply to barbs becoming a minor civ I think. Becoming major civ doesn't need a reward, it IS the reward.
But for barbs becoming minor civs they might need something to stop them getting immediately stomped. For me it is quite common to ignore barb cities because they aren't really a threat (they won't spread), but as soon as they become a civ they are a competitor for resources, and thus killing them quickly becomes more attractive.
However maybe it is still fine, and if new minor civs get stomped that is just natural selection! Maybe it should be a setting: new minors and/or majors get reward or not?
Barbarians becoming minor civs gets a huge bonus when becoming a minor civ, this is a bonus that those who were along since turn 0 will never get.
What I'm saying is that there is no more reason for barb civs and civs emerging from revolutions to get more bonuses when becoming a major civ than for players that were along since turn 0.
So if players that were along since turn 0 should not get a single bonus when becoming a a major civ then why should players that emerged from barbarians or from revolutions get a bonus when becoming a major civ?
Barb civs already got a huge bonus long before they become a major civ so why should they get a second one if it's not a rule that applies equally to all minor civs?
My opinion is that either all minor civs gets the bonus when becoming a major civ or none does.
One can adjust some of the bonuses from becoming a major civ in BUG options, and these settings treat new world minor civs differently than old world minor civs.
The current code does actually give a much bigger bonus to new world civs becoming major civs than old world civs, this is a system that is meant to simulate how the natives of the new world, who could only have emerged from barbarians (else the land mass wouldn't qualify as a new world), ramp up their capabilities when having made contact with enough old world civs. Making them a stronger force to be reconed with, not immidietly when the new world is discovered, but when old world civs have infringed on the new world to a specified amount (lots of BUG options to decide what that amount is).