To add my 50 cents, regardless of his intentions, Ashoka's decisions affect us terribly to this day.
Look no further than our neighbor, China to see how an Emperor should've ruled his Empire.
Qin Shi Huang, the first emperor to unify China took a few forceful decisions that affect the Chinese to this day, positively.
The decisions of Ashoka—Pacifism, non-expansion, non-unifying standards, etc cost India heavily.
1. Pacifism made the army weak when the economy was at its peak.
China at the same time did the opposite. They needed an army because they faced barbarians. It is a proper justification.
But India too needed an army. The enemies of India historically came from northwest. So, when you have arguably the strongest empire till then, you should've gone ahead and exterminated the barbarian tribes.
Expand your outreach.
2. Religion vs State.
This is an Indian vs Chinese thing.
Rulers shouldn't rule states based on Religion. The emphasis of states should be on stability, security and growth.
For one, I believe a leader could follow religion personally but as a ruler, he must never let it influence him.
Take the good decisions for the state, even if they go against the religious principles.
3. Ashoka failed to instill a sense of oneness in the Mauryan Empire.
India is a large nation, very tough to govern. But so is China, even though China back then wasn't as large as India.
But the interesting fact about China is that it isn't the Emperor that ran the empire but the officials.
A strong official system was what made a unified China durable. These officials used the same written script, followed a same system and were rotated regularly so that they don't amass too much power.
4. Caste System.
Varna System was an efficient model for functioning of society while Caste System was a terrible curse—personally, I think this is the biggest reason India suffered so much throughout history.
Ashoka had a chance to reform things. Either brutally once and for all or through successive steps.
If he had reformed the caste system and by reform, I mean either abolishing it completely or making it fluid—anyone can become a kshatriya after training and joining army, anyone can become a brahman learning vedas and passing a central entrance test, etc et.
My first post, this isn't very coherent, apologizes.