I agree with you. I don't know much about Tharman, but I know it's not exactly a monumental task for anyone to be a better PM than the incumbent who has set a really low standard. You can't get any worse than it already is.
As you can see, many posters are already drawn into the debate of whether they want Tharman to be the next PM. Many have forgotten that from the perspective of Opposition contesting in AMK, it's not about who is going to be the next PM. It's just a ploy to lure the 60.1% dumb skull in AMK to consider voting for the Opposition for reason other than they want Opposition in Parliament.
I see Singaporeans haven't been watching enough of Romance of the 3 Kingdoms. When you have Opposition drumming support for the enemy's deputy to be the next chief, the situation can take an unexpected turn. Just look at how much damage Ah Gong had caused WP after he publicly praised LTK.