On the contrary I find this regional party system the main reason for most of the corruption. Akalis, INLD, SP, BSP, AIADMK, DMK etc etc etc have always made headlines for their corruption and the reason attributed is simple rotation of power and benefits of divided public.
Here is the invisible side of regional politics: the buying and selling of MLAs and MPs happen because of fragmentation of votes by regional parties. Parties with 2-3-4 MPs do not support any govt for nothing, ministerships plus money is often bartered. Also, it is due to the regional party system that government can not take strict actions. In first term Left abandoned UPA on all decisions related to US, even those which were thoroughly in our favor and in UPA 2 Mamta's fiascos are well known.
Regional parties ke sandharb main arz hai:
राम नाम की लूट है लूट सके तो लूट... कल को फिर पछताएगा जब कुर्सी जाएगी छूट
In my opinion regional parties should be restricted to state level elections at best.