Some coolstory to start with:

Citizens: We rebel! You assholes colonized that gas giant!

Governor: But it is populated by race who are living for their known history on it! And they are quite happy here...

Citizens: We don't give shit! You will pay for this! Rebellion! Kill and plunder!

Governor: But what are your demands then!? We can't decolonize a planet!

Citizens: We demand... demand... We will just starve ourselves so you'll know to not mess with us!

Current happines works just like this. It is really stupid: all colonized planets inflict negative happines, regardless if they are populated by species who are adapted to their climate or not, if populated at all. Colonized arid? Blam! Get your -20!

My suggestion is to make happiness work like in Stellaris: pops who populate their native climate are quite happy with that and produce at maximum capacity, while other pops not so, and that purple bar on topleft should be just average happines of all pops.

Guys, take best from the best. I liked how community manager said in AJ review that they are going to put emphasis on population (also that 'you know' refrain), but apparently Stellaris does better job at it at the moment (I get it, released game vs early access, but whatever).

P. S. Also, it is always fun to watch how your pops are happy to starve themselves every time a random colony on the other side of the galaxy is created.

i think that when inter system travels will be added they may specify unhappiness by race (lumeris unhappy on arid the most, etc etc)

The same way voydani shouldn't be unhappy since they work from their ships but hey balance :O

Yes, that's also how Stellaris works. No matter how rebellous guys are, their food production will not be lowered below content-happiness level.

Wouldn't it be great if they didn't just go on hunger strike but had proper riots and broke stuff, like burning down all their infinite supermarkets. That's like what happens in the real world, let's do it!