We should pick players based upon their domestic performances over more than one season - there is no need to stick to flawed selections. The flaw with RP Singh and Sreesanth is that they have been living off one FC season, which was long ago for both of them. RP Singh got a whole season in this year, which is valuable and he showed improvement throughout the season, originally taking wickets at 40 and it going down nearer to 30. A few seasons of long overs are priceless for a bowler's development, just ask Zaheer. He got three long seasons in, in 2005-7 (ish), and it did him the world of good.
Tyagi would not be the right option for Tests, he had a strong debut year, but has had two poor ones after that. A bowler who cannot take wickets in FC cricket has little chance of having a prolonged impact in Test cricket. Look at Zaheer Khan, whenever he plays domestic cricket, he cleans up with 3 or more wickets. He may pitch it up and be expensive, but he gets the wickets because he understands his bowling and knows how to get wickets - something which I do not think that any of the current crop of Indian pacers know how to do.
I think it may be the time for IKP to make a return to the fold. He has had two very strong FC seasons with ball and bat. He has not been perfect, but he has got overs under his belt and offers the batting, which is a bonus when you have no standout bowlers. I would like Bose or R Vinay Kumar to get a go in Tests, but neither looks likely and IKP is a good option, imo. I do suspect that he is injured atm though, as he has not played for Baroda for a while, I hope it is nothing serious.
I just hope we do not stick with Mithun before he can suppliment his first season. Mithun himself acknowledged that a plethora of bowlers have strong first seasons and then they fizzle out - kudos to him for doing that, but he should play one or two more full seasons before talk of Test selection begins.
As for OD cricket, the Vijay Hazare Trophy appears to be such a haphazard affair and the Deodhar Trophy is so short, that traditional methods of selecting players who have done well and are in form is probably in order - just as long as we do not rush anybody who is not fit, into action - such as Sreesanth, in recent ODIs.