Not only the number of punishment's verses are less than the number of mercy's verses, but the mercy is the base about Allah.
Question:
Why are most of Qur'an's verses about hell?
Answer:
It should be noted, that the number of verses, which are about "mercy" and "forgiveness", is more than 560 times, while the number of verses that are about "divine punishment" is just 400 times.
Moreover, Allah (S&T) has decreed mercy upon himself in the holy Quran:
(And when those come to you who believe in Our verses, say, "Peace be upon you. Your Lord has decreed upon Himself mercy: that any of you who does wrong out of ignorance and then repents after that and corrects himself - indeed, He is Forgiving and Merciful.") [1]
In this world, if someone were to undergo surgery to recover and live a healthy, nobody consider it as a punishment, rather, kindness and compassion toward him. Most of punishments, in the holy Quran, are like this.
Note:
[1] Surah AL-AN'AM, verse 54: "وَ إِذَا جَاءَكَ الَّذِينَ يُؤْمِنُونَ بِايَاتِنَا فَقُلْ سَلَامٌ عَلَيْكُمْ كَتَبَ رَبُّكُمْ عَلىَ نَفْسِهِ الرَّحْمَةَ أَنَّهُ مَنْ عَمِلَ مِنكُمْ سُوءَ ا بجِهَلَةٍ ثُمَّ تَابَ مِن بَعْدِهِ وَ أَصْلَحَ فَأَنَّهُ غَفُورٌ رَّحِيم"