This factor impacts a lot of the things you've asked about, so I'll explain it here first:
Empire at War has an unavoidable bug where after a certain amount happens in a GC, the game essentially freezes and you lose control of your units, making the game unfinishable. This existed in the base game, and has never been patched. Therefore, the more you have happening in a GC, the sooner it will happen.
Warlords, Imperials, Hand, Attack moderately Sad
Republic attack way more.
This is a result of the aforementioned freeze. The more the AI attacks, the more they attack each other, the fast the casualties stack up and the sooner the freeze occurs. In previous versions there was a tendency to have lots of attacks, but they were usually insignificant. In 2.0, the emphasis is on fewer battles, but overall they tend to have higher impact. This way you're technically getting more action, but with fewer annoyingly pointless small battles which impact your ability to finish a GC.
More Planets! Which is awesome! Less planets, and western half of map void of planets wtf?
There are more planets in the mod in general, however there are about 10 fewer in Art of War now than there were before. From like 103 down to 93. This again is a result of the freeze bug thing. We cut some of the less important planets so the scenario would actually be finishable. The reason there's fewer planets on the Western side is because we moved all the planets to their canonical positions. The WTF should be why they were over there to begin with, not that they're now where they should be. It's kind of like playing a TW game and asking why in a game focused on Europe you don't move Italy over to North America because "look at all the free space."
Warlords actually attack other factions Warlord's do absolutely nothing. Wtf.
and take over planets!
This varies between the GCs. In all of the GCS but the full Art of War GC, the minor factions are active. In Art of War they were disabled on the full galacit map because again, the freeze would occur about 100 weeks earlier, even with fewer battles and planets. If we wanted to have the minor factions active in Art of War and have a chance of it being finishable, we'd need to cut out about 30 more planets. We have that scenario already though, we called it Art of War Light.
Lando and Leia have Hans voice! Lando has no voice, and Leias MIA?
We've been unable to get Carrie Fisher and Billy Dee Williams in to record their lines as of yet. We decided that having a unit with no voice is better than having them all have Han.
Republic artillery droids scan map yay! Republic artillery droids no longer scan map wtf?
Land battles used to be just sit back, use the spotter droids to ping places and turn land combat into a point and click adventure of artillery and bombing runs, probably the greatest contributing factor to them being completely annoying and mind-numbingly dull. We wanted to get rid of that.
Republic soldiers not being able to crouch down wtf?
They had no animation, and that ability doesn't work without an animation.
Computer Controlled Pentastar does nothing! Doesn't attack anybody wtf?
Again, this is only the case in Art of War, not in
any other scenario. You can either have a big scenario, or you can have one with all the factions being actve. You can't have both unless you want the game to become unplayable around week 100.
Plus I liked seeing in 1.2 the Hapes actually fighting along with everyone else as well. They held 12 planets at one point! In 2.0 Hapes is gone, and no one seems to do anything. Someone here posted that he had 17 independent little factions all running around killing each other in his modded version. While 17 is maybe too many, I liked seeing the Warlords fight the Imps, and Hapes fight the Imps ect. 2.0 doesn't have that...
All of these things are still there, just not in Art of War. They're in basically every other scenario. If anything they're more present now than in 1.2 or 1.3, it's just that we now made it so people could actually finish Art of War.