a) Palpatine's "running" tactics can be justified by his intent. He wanted to either a) escape or b) prolong the fight to ensure that his men arrive so that he is guarenteed a victory.
b) Palpatine and Yoda both fight with lightsabers, and that is ultimately left a stalemate (however, the RotS script says that Yoda managed to outspar Sidious in the end). Even when they fight on even ground, Yoda is still unable to overcome Sidious.
Sidious flips onto the Chancellor's podium as it rises out of his office. He lands right on the Chancellor's block (the mini-platform in the center where he stands in all of the Senatorial addresses). Yoda follows suit and lands on the railing in front of him.
Yoda's style of lightsaber combat requires acrobatic maneuvers and intense speed to compensate for his stature and so forth. Therefore, it only makes sense that he is in the only real position that he can fully utilize his lightsaber form. He is still unable to overcome Sidious.
They are, by the way, meeting each other blow for blow. So it is not Yoda swinging and Palpatine blocking.
c) When the camera pans back, we see Yoda leap forward and force Sidious onto a lower block, where Yoda uses overhanded swings to try to forcibly beat Palpatine's lightsaber away. But Palpatine forces Yoda back on the outside, and retakes the center position.
Yoda continues to try to break Palpatine's "defense", by flipping around the circumference of the podium. Finally, they get into a saber lock, which Yoda manages to break. They fight for a second more, and then end up in a second saber lock, which ends up with Palpatine "roaring".
d) When we return, Palpatine is without his lightsaber. The RotS script says that he was disarmed (but it should be noted that the script's account of what happened differs from the movie).
The script says that Yoda disarmed Palpatine, and then, for some reason just jumps to a Senate pod. Odd enough for a being whose single goal is to kill his enemy. However, if Palpatine were disarmed, it speaks well for him to be able to evade a fully-armed Yoda and be able to put some considerable distance between them.
e) Yoda jumps to the first repulsor-pod. Palpatine cackles and rips three of them from their moorings, and throws them directly up behind himself - thus in direct defiance of gravity. He then uses the Force to take hold of one, and chucks it at Yoda.
Each one he chucks, Yoda dodges. But the final one, Yoda falls. He puts away his saber as Palpatine chucks the last pod. Yoda catches it, spins it, and sends it back while Palpatine cackles (odd behavior on Palpatine's part as well . . .). As the pod gets forward, Sidious stares at it, cocks his head, and says "eh?". Then, he snarls and jumps away at the last moment.
f) Palpatine hands feet-first in a repulsorpod and looks around. Yoda jumps up and lands on the rail and ignites his saber. Palpatine reaches out and blasts it from Yoda's hand.
Yoda nearly teeters off the side, but regains his footing and catches the lightning. Palpatine uses his other hand to blast some more lightning, but Yoda catches it in his free hand as well. Palpatine, who is the one generating the energy, moves closer to Yoda - who must remain stationary.
Yoda grimaces and leans back. Palpatine cackles. Yoda glares at him. Palpatine gasps.
Take a note:
The "energy ball" formed from Palpatine's coiled lightnings is closer to Yoda than it is Palpatine. I will try to provide you with an accurate shot of this. The lightning is pouring from his fingertips and just stops short of Yoda's.
Yoda does not push the energy ball at Palpatine!!! contrary to popular belief. The energy ball never touches Palpatine.
What Yoda did was put the energy ball right in between them both. It goes off and flings them both back.
Ending in a stalemate.