Well crowd attendance in a test match is a problem even with well established grounds.Crowd in matches indore vs nz,vizag vs eng are much higher than regular stadiums.My view new stadiums can be developed than restricting to main centers.
You cant feed people T20 and then try to develop test cricket. Test cricket should be kept elite to the established grounds which have a rich test cricketing history and has all the chances of getting consistent crowds. Also I did include Hyderabad (Vizag) in my test grounds list. I am not sure about Indore though, but if it keeps getting consistent audiences irrespective of the season or the time when the test is played, then yes it can be included. Places like Pune, Dharmashala, Mohali, etc should not host test cricket. Especially Mohali has even acquired the reputation of becoming a poor test venue with very lacklustre attendance.