[hobin]

No, because the 'I think' does not mean what you think it means. You can't take it out of its social context, which is to inform people that you assign a lower certainty to the next thing you are going to say. (Of course, you could say all that, but that would make most conversations very pointless and annoying, as I can say from personal experience.)

[pizza]

You could say "I think the economy will be the most important issue in the next election", but you could also say "The economy will probably be the most important issue in the next election," which sounds clearer, as well as less refutable.