Other bowling options are Sreesanth, Nehra and Ishant. Your idea could work if the part timers have good day but would also let the opposition recover from collapses if there are any if they don't do well. No players in the team now to finish things off when we have an advantage. Don't see these issues troubling us much in the league stages but would become serious only from the QFs. Will need luck to reach the semis but can't see us in the finals.
I would say India has a good chance to reach the finals. I don't know why you are so skeptical. They would need luck to NOT make it to the semi-finals. They have a superb batting line-up and with the kind of form Tendu and Viru seem to be in of late they can bloody murder the opposition. But I agree they might not make the finals. I think they will lose out in the semi-finals like in 96.
Death bowling will be crucial (as almost always in ODIs). The best death bowling is with Pakistan and Sri Lanka at the moment. Umer Gul is a bit out of form but when he gets going there are few better yorker bowlers than him. He is the most successful T20 bowler. Malinga is another one who is superb in death overs.
After the recent series between Pak and SA, I have downgraded SA from being one of the top 3 favorites to win the WC. Their performance was quite terrible especially under pressure. In fact for once they looked worse under pressure than Pakistan (a side generally renowned for crumbling under pressure).
Australia are nowhere near the force that they were in world cricket but still competitive. I just don't see them winning the world cup this time around. Their bowling and batting is just not as good as it used to be. And after the recent SL-Aus ODI series Australia seem to have gone down more than a bit.
Sri Lanks seem to be favorites this time around. Unlike last time when they were not fancied before the WC. This time around they are. And seem to be the most balanced side in terms of batting and bowling. Their fielding too is generally of a good standard.
England are a good side but I am not sure how they would perform in the sub-continent. I don't think that the SC has been their best hunting ground. I am not sure though.
WI, Ban, and Zim might win a few matches here and there but I don't really see them giving a tough time to too many.
NZ after their disastrous tour of Bangladesh might not be hot favorites to win the cup. So no comments on NZ.
That is my analysis.