Crusade will change a lot about my arguments. Also my experience is based on medium to huge map sizes (~6-12 planets without conquest per civ).
But for the current game, I would argue the following:
My question is, as with the title, do people think that adding the additional 4 class 1 planets will be op once you start to unlock tech which gives you more tiles?
Let's forget about the tiles for a second.
What do you pay for colonizing a class 1 and what do you get?
You pay the manufacturing needed to build a colonizer (cargo hull with colonizer module and nothing else) and the time lost for population not producing anything during the travel.
What do you get:
- 5 food
- 0.2 growth
- 1 production
- 3 adjacency for Manufacturing/Research/Population and Wealth.
In short: it is amazing for its cost.
What happens next? Well you use the production you have to pump out economic starbases. By hitting 6 worlds at the same time, they are extremely low cost improvements again (2 constructors in return for +5% production and a basic factory on all worlds essentially).
So what about the drawbacks of class 1 worlds? Since you have many, just screw building hospitals, you will be far ahead in population growth anyways. Screw building planetary factories or research stations, since you can put those on starbases. The only thing you will build once you can terraform, are food improvements, which will scale nicely with all the starbases you have. Screw building scouts, developing these six worlds might be all you need.
Btw, which techtree will you use? If you are contemplating something like thalan or drengin: Thalans benefit form hives a lot and have the hyperion matrix, which affects all planets. The drengin have their slave hubs, which are easily one of the best colony uniques in the game. You will get 6 of these very early!
Im wanting to add them more for flavor of the system as I plan to use it for a custom race from a book whos mythos has all these extra barely habitable moons/planets.
I think you could go all the way and make some of these additional worlds toxic or radioactive, without exceding the total systemclass of 16, if your race has adaptable.
Long story short:
I think 8-4-1-1-1-1 would be overpowered even before considering terraforming. But by the end of the day, you are playing with it, don't push the balance so hard, you will lose motivation
I hope this was somewhat inspirational to you.