So if you look at previous civ titles. For most of civs histories, growth had a "HARD CAP". You could only get a city to X size and then it stopped growing period. You needed buildings like the sewer system to grow past a certain point. But once you did, you were on your way.
In Civ IV, growth caps were softened a bit. In Civ IV when a citizen became unhappy it stopped working, effectively making your pop "useless". However, the second you got more happiness, that citizen was back in action, working to full.
In Civ 5, growth cap was softened a bit more. Now unhappiness gave you a very strong curb on growth (-75%). But once again, once you built a few happiness buildings, you were back in good standing, and rocking again.
There are two common themes in the civ games that VP has not carried over, which is why there is a key difference.
- Growth has much stronger in previous civ games than in VP. Civ 4's tiles were often very powerful (as was the slavery mechanic that converted pop into hammers), and so growth was strong. Civ 5 pop and science were linked, so a high pop civ had a strong science foundation.
- Happiness had direct and immediate ways to address it. You build X building, your happiness problem is solved, and you move on. Meanwhile, you knew exactlly how much growth would trigger more unhappiness, so you could plan for it. VP's system is much murkier, and your decisions can haunt you for many turns to come. If I make a mistake in classic civ, I just turn to my happiness tools, and I bail myself out. In VP, its "suck it up buttercup" for 50 turns or more because you "played wrong". There is no quick fix for unhappiness, heck even building PWs in every city often is not enough.
So with respect, teh design of Civ and the design of VP are quite different when it comes to happiness management. No civ game has ever pushed the kind of happiness management that is in VP, and I think there are good reasons why not