Compared with the Galactic Republic at its peak, the Galactic Empire controlled roughly a third less territory. However, those regions had originally been lawless fringe areas of the Galactic Republic, so losing them was no great loss.
Overall, the Galactic Empire was indeed stronger than the Galactic Republic.
But this so-called "strength" was not because Palpatine governed diligently, nor because the Galactic Empire's system was somehow more advanced than that of the Galactic Republic. It was purely because the Galactic Empire's exploitation was even more severe.
Under Palpatine's rule, the Galactic Empire employed extremist, authoritarian, and even terrorist methods, plundering and extracting all wealth and resources from the regions under its control. Backed by the Empire's immensely powerful fleet, his grasping claws even reached toward those Core Worlds that had once supported him.
Palpatine was truly shrewd in this regard. Step by step, he gradually stripped away the power of the Inner Rim and the Core Worlds.
When he had first become Chancellor of the Galactic Republic, his power had still been extremely weak. Compared with the great aristocratic houses of the Inner Rim and Core Worlds, which possessed endless wealth and resources, he was like an ant that could be crushed at any moment.
Yet during his first term, he had been cautious and meticulous, walking on thin ice as he won the favor of most people. All the while, he secretly accumulated power, courted supporters, and gathered leverage and scandals on his political enemies.
Then, during his second term, he struck hard and crushed most of his political opponents in one blow. From then on, he moved through the Galactic Republic's political scene like a fish in water.
Next, he sparked the Separatist crisis, shrouding the Milky Way Galaxy in the clouds of war and making everyone fear