Oh yeah. It's pretty tough to get any planet above 20B these days. In previous versions (DL v1.2) before significant nerfage to approval buildings it was possible to achieve planets of 100B but now it's foolish to even try.

Depends on which version of the game as to what pop points are easy to hit and allow you to keep a reasonable approval level. The size of your galaxy and the number of morale resource mines you have makes a big difference as well. A decent rule of thumb in a gigantiac galaxy with about 6 morale resources is 13B for anything PQ10 to PQ7, 6B for PQ6 or less and 20B for anything PQ11+. One reason is the 10% approval bonus that PQ11+ planets get. The other is simply a matter of the number of planet tiles you have to give up for food/approval buildings. In a medium galaxy or below I'd probably hold every planet to 13B and may even consider keeping PQ10-7's at the starting limit of 6B. Generally I shoot for 2 top level farms and 2 VRC's to hit 20B but if I only get 4 or 5 morale resources I may have to go to 3 VRC's.

The above is primarily for DL although these levels aren't too far out of line for DA. DA does have the extra "cap" on morale resource mining and somewhat more severe pop approval penalties, but if you're willing to let your approval sag to the 40% level on your most populous planets then you can do 20B in DA as well (again gigantic and maybe huge galaxies only).

galciv2 let's you make the choice to use or not those kind of tiles

it's kind of the same reason why there's anomalies with 1bc worth of coins

as an example a PQ 24planet (quite findable in immense galaxies in TA)

with 20% PQ bonus from ability + Drath tech tree and +3PQ building + 1 from each terraform level

should be 24*1.2 +3+1+1+1 = 34 PQ planet

now if there's a food bonus tile on the planet, it could probably be used, moreso if you build your shrine of the mithrilar (+75% morale) along with a few other good morale buildings

then the planet could be used as : source of income + troops

It's got to be a byproduct of the days when you could have 20b+ with ease and Stock Markets gave Morale.  It's something I think that's fallen the wayside though since.

As for the AI always placing it on Thala, it's the same problem as their overuse of the Embassy...lack of planetary improvements to place.  They don't have a 2nd planet in their system, so their colony ship probably won't see a planet first turn.  What's the first thing you'd want to place on a planet...a factory.

Ever since I accidenlty placed it on a farm tile, I've become a convert to not place it on Thala.  I got into a pattern of placing all factories on farm tiles just so I never accidently placed a farm there.  Well, silly me forgot about the food component and cringed when a 300% food tile saw a +8 food building.  At least the planet self-levels off by hitting 20% morale...  It really made that planet my population center for troop transports though lol.

And just think, you can drastically reduce normal events in the 2.0 beta

I'd say to only jump in if you don't mind things possibly being buggy when you do something.  If youre into playing the game just for the sole purpose to have fun, Beta's may not be your bag.  Now, if you love to discover things, even if it means it's a game breaker and you cannot finish that sandbox game, then by all means...join in the fun.

Note, that doesn't mean the beta is THAT buggy.  I'm just saying that only people who don't mind finding bugs, or purposely try to break the game to make bugs appear should be playing a beta of a game.  There are those that during a Beta will scream on why a bug like X got in there in the first place and that the devs should be replaced by un-trained monkies.

I'm sorry to say that I liked TA back in it's beta stages more than I do in it's live form lol.  Finding problems is just something I enjoy doing.

Hear that Not-MoM developers?  /hint /hint

I mix and match farms and bonus tiles to get the population I want without building more than one farm.  Intensive farming + 100% bonus = 20b, easy to keep decent approval with some morale resources.  Advanced xeno farm + 300% bonus is the same I think, and cheap to build.  In my current game I've got a planet with a pop cap of 32b, it maxes out around 29b I think.  It's class 34 and has my economic capital, plus the politcal capital, Oracle of Krynn, and Order of Krynn on morale bonuses (one of those might be on an influence bonus, can't remember).  It also has the Krynn temple and consulate, and rest of the tiles are stock markets.

The income and influence generated are quite spectacular