I wish there was a way to turn off espionage

That is the main reason I never bought the expansions to GC2. It just created an unacceptable level of micromanagement, and hassle.

The asteroids were another. All they did was create another type of resource that you had to direct to a certain planet, with a little graphic bling. Sorry, but more micromanagement of resources is a bad thing.

The original GC2 was, and will always be, the best. All the expansions ever did was to add more micro-garbage - but never any better gaming.

You grossly underestimate the addition of the civ-unique tech trees. That added no new top-level UI to micro-management but added respectable variety to the game. I was stuck in a deep Thalan rut for ages, but TA got me regularly playing as Arceans, Altarians, Iconians, and Yor.

The asteroids were a final disappointment to me. But I like 'good' micromanagement, so I wouldn't agree with you that they're a useless bother if the devs had retained the idea of assigning an asteroid base a role (I'd have enjoyed 3 flavors: production, research, or cash).

The espionage problem charon2112 describes seems to be a play style thing. It almost never happens to me because I tend to stick to the middle of the power-ranking pack on very large maps until well into the game. By the time I'm strong enough to start attracting heavy espionage attention from the AIs, they've burned most of their assets amongst themselves and I have a fat stack of reserve spies to zap the occasional intruder.

That may be it, I grew a large military very fast, twice as big and twice as fast as any other civ.  that drew attention.  

Yep, and sometimes the notice (to the right at the screen) that a planet has been infiltrated by an enemy spy lags for a turn or two.

And ships sometimes circumvent asteroids, sometimes not, it's a mess.

The easiest way to deal with spies is to build Counter Espionage Centres.  Especially on planets which have bonus tiles in use, but also on any planet that has a significant number of economic buildings.

It won't stop spies completely unless all your planets have them, but the spies will no longer be able to debilitate your economy.

I'm pretty sure that the whatsis-blocks in the map window consistently report late on enemy spies. Whenever I notice an espionage wave starting, I check the Espionage tab directly before ending turns. You can kill enemy spies from there and then see them reported in the whatsis-blocks at the start of the next turn; follow the block-link to the planet in question, no spy.

Re Counter Espionage Centres, their value also is probably affected by play style. I almost never feel a need to build them, have maybe done it three times in tens of gigantic and immense games, and then only on very large worlds that seemed to be unusually attractive to the AI spymasters.

So I ended up quick buying a counter espionage building on all of my planets--about 50, yeah it was expensive.  I thought it would remove existing spies, but unfortunately it didn't.  Eventually I nullified all foreign agents and won a tech victory...