I guess, Colors would not dare to enter any regional market any time soon as no region, they lead the market share. In Bengali and Odia market, they have successfully destroyed popular ETV brands. Now hardly anyone watch both Colors Bangla & Colors Odia channels.
In tamil market, till now they (Colors Tamil) are unable to grab audience's attention.
In Marathi market, day-by-day they (Colors Marathi) are lagging behind far from leaders Star & Zee.
In Kannada region, Colors Kannada have been already dethrown from leadership position by Zee. Colors Super is too near to shut their shop.
Only in Gujarati market, Colors Gujarati still dominate the market as only because it is their monopoly market, no competition is there.
They are still frightened to enter Bhojpuri like small market also. Rishtey Bhojpuri was planned about 2 years ago, but no news still now.
In a word, we can say, Colors have no powerful impact on regional market as like Star & Zee.