Sorry, eventhough I have seen all the complaints, I disagree.
I've nuked posts that where under 2 FFs, 1 mk3 and a lower mark, Spire post are weak compared to those, and with a churgical strike they can be taken out quite easilly.
Having a Spire-shield under a mk3 FF can be painfull, when you need to nuke it to get rid of an Eye, but often taking the planet makes it a lot easier. Anyway, that happens once in x games*
*
x = no of games played
y = average no of planets per game
z = change of a nasty situation happening in your current game
1/(x*y)=z ... <= very small number
last 5 games I played on an average of 100 planets, and it happened once (I played 3 of those 5 game taking every planet)
1/(5*100)=0.002 ... <= chance of the next planet having a nasty situation based on my previous games.
When you end up with a formula like
5/(1*80)=0.0625 ... Thats quite a bit bigger number, but you still need to take 16 planets before you will see the nasties happen, on average. That would leave you enough room to take 15 planets, bolster your econ/defences, and accept the hit when you clean the 16th planet.