Rajsekar, hard to disagree with most of your points but this one

That's why every single Raaja-Rajini album is a golden hit. Numbers speak the truth. There is not even a single Raaja-Rajini song which can be called subpar or mediocre.

You would still say this after listening to "Pandian" songs? Some say it was composed by Karthik Raja but it had Raja's name as the composer and the songs were mediocre. Lyrical quality, that you lament is so poor in today's songs (which is true), was abysmal. "Pandianin rajiyathil uyyalala", for one, is as bad as the lyrics written by Rokesh. "Pandiana kokka kokka", OMG. "anbe nee enna" was the only decent song in the whole album. So, let's simply accept that Raja has his share of bad compositions for Rajni movies. Same for Kamal ("Maharasan", the music was terrible). However, considering that the rest of Raja's music for these two stalwarts was brilliant, these two duds can be forgiven.