S.Gurumurthy in the New Indian Express on the Vijayakanth factor in this election:

Imagine if the AIADMK alliance had roped in DMDK. How many seats would Vijayakant have shifted to the AIADMK alliance from the DMK alliance? Hold your breath, 105 seats, assuming that he shifted all his votes to the alliance!

Yes, if the AIADMK alliance had brought in Vijayakant into its calculus it would have won not 69 seats, but 171. Imagine this had taken place, what would have been the tally of the DMK. Just 53 seats instead of 96 it won! How about the Congress? Just 3 instead of 37! PMK? Just one instead of 17! CPM? Again, just one, instead of 9! CPI? None instead of 7! Unbelievable, yet, true.

He goes on to say that Karunanidhi would have taken Vijayakanth in if he were leading ADMK, and credits him with identifying that this election would be won or lost by sheer alliances:

The way Karunanidhi structured the DMK-led alliance indicated his understanding of the mood of the people. He judged that there was no anti-incumbency, nor any pro-incumbency, mood in people. He knew that Jayalalithaa had vastly improved her position in the last two years and so he needed the alliance even more now than in the 2004 Lok Sabha elections. So he rooted for electoral physics.

In contrast, save for her wooing Vaiko, Jayalalithaa relied more on electoral chemistry to overcome the effect of electoral physics. Perhaps she was also influenced by pollsters who had initially predicted her victory. The result was that she left out Vijayakant and thus did not complete the process of bipolar contest.Thus, the election threw up the Vijayakant space between the bipolar alliances incomplete on one side. The result was what should have been a resounding victory for her alliance turned into a defeat brought about by an omission, and a costly one at that. It is Karunanidhi's greater reliance on the power of alliance as compared to Jayalalithaa's that turned the results in his favour and against her.

All fine and dandy. The analysis would make sense, except for one big assumption.

Gurumurthy blindly assumes that if Vijayakanth had aligned with the ADMK, he would have won as many votes as he ended up winning. That, to me, is a big and unreasonable assumption. The main reason why people voted for Vijayakanth was that he was different, he didn't align himself with either of the Dravidian parties, he provided an alternative, idealistic it may be.

Imagine Vijayakanth turning an ADMK supporter, simply praising Jayalalitha in his speeches and asking people to vote for ADMK. Would his credibility have taken a beating? Absolutely. Would he have been relegated to the likes of Vaiko and Sarathkumar? Probably. Would he have won these many votes? No, I don't think so.