About the "it's too easy to free the whole planet, and its too easy to free ships in general" and the "planet's don't have much on them", I suggested to give the AI more on each planet, but make it harder to free AI ships. This would make planets more challenging because they have more on them, harder to free the whole planet due to there being more on that planet on average, and harder to "bait" AI defenders because it is not only harder to free the whole planet (again, due to there being more on the planet), but harder to free defenders in general (because each unit wouldn't free themselves at a sneeze).
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Part of the problem is that systems are small these days. Lots of things have ranges in excess of 10,000 distance, and plenty of stuff has speed over 100 as well. This means that as soon as you've entered a system, pretty much everything can be involved in the battle in no more than 20 or 30 seconds.
In some way, the new Special Forces are exactly such a thing. Wipe out the planet before the blob of SFs arrive 
Except that now there are redundant versions of these things.
Super Guardians = Golemite / Crafty Spire AI for everyone.
SF defensive fleets = Hybrids in Defensive mode.
A couple of other ideas have been floated, but they seemed similar to existing idea, i.e. new AI Eyes.
While I'm glad to see something done to give the AI an actual reactive feel, I can't help but feel that SF fleets are nothing more than a defensive only version of Hybrids. Super guardians would be a scaled-down, defensive only version of Golems/Spirecraft. Not necessarily bad, but kinda makes those AI types silly.
The complaint about taking planets being to easy has a couple of causes that I can see:
1) Each planet stands alone. The AI may have 100,000 ships in universe, but only 1000 on any given planet.
2) There's almost never any need to act against more than one planet at a time.
3) An AI planet's main defense is not the ships on it, but the AIP increase the player takes if the system is destroyed.
4) Planets are DEFENSIVE threats, aka a threat to an attacking player's fleet only. Waves are the only real threat to a player's survival.
There are things that can be done to address these issues.
For item #1, the Hybrids and the new SF fleets are attempts to compensate. I'm not sure what else can be done, except uping the scale of the response ("Alert! The AI Homeworld has dispatched a Hunter/Killer to deal with your invading fleet! It will arrive in X:xx!")
For issue #2, it has been suggested that there could be special timed events (like the Rebel Human Colonies) to promote spreading out. Unfortunately, the only 'penalty' the game has against players in to increase AIP, and there's already a lot of stuff that does that.
item #3 is more meta-game, not tactical - but it makes the point that what the player is doing WILL have consequences and increase future difficulty. It's also the reason high-level players attack to neuter rather than kill. Changing this changes the entire structure of the game.
Finally, #4. There's really nothing to be done here unless waves are dramatically reduced in size/power. Then, there would be room for the AI planets to get their offensive act together. Right now, however, there's only threat. And threat is basically a next Wave "+ x ships" counter. 4 is also complicated by the fact that humans tend to minimize exposed surface to the AI, through the use of whipping boys, gate raiding, Warp jammers, etc. Switching the planets to having offensive threat obsoletes all of those.
So, what do people actually want changed? I think Keith had it right: The real problem is not that it is too easy, but that it is too uninteresting. If all planets are the same, then all your battles are the same.
The game already has plenty of things that are interesting - Think of the Peacemaker AI type. Would people like it better if more planets had things like OMDs, Grav Drills, Planetary Cloakers, Interplanetary Munitions Boosters, Black Hole Machines, Armor Booster/Inhibitors, SuperFortresses, CounterSpys, Dyson Spheres, Radar Jammers, Neinzul Rocket Corps, Neinzul Nests/Clusters, Troop Accelerator, Alarm posts, Devourer Golem, Raid Engine, Attritioners, or AI Eyes?
Every one of those has some impact on how to approach a planet, including determining if it is even WORTH messing with a planet.
Do people just want more planetary specials? Maybe a planet with a Grav Drill, Planetary Cloaker, and 2 SuperFortresses? Would anyone consider that "too easy" or boring? Actually, i think that'd be pretty awesome, myself... Maybe a new AI Type - the Heavy Builder, that gets multiple specials per planet.
