Illegal mining, denotifying land for family gain are two key allegations of corruption and bad governance against him. Allegations of thousands of cores of loss to the exchequer is something he could not escape for long. It caught up with him and the rest as they say is history.
On its part the BJP had very little choice. It was important to project the image of a party intolerant of corruption. Else its crusade against the Congress at the Center would have lost steam and it would have lost the only opportunity to stage a comeback. Down South the ground reality too is bleak for the Party. It has no hope of coming to power in Tamil Nadu and Kerala in the near future. The two states are unique in their own way. Andhra Pradesh too is seemingly out of the bounds for the Party with regional party leaders Chandrababu Nadu and Jagan Reddy going strong. So for now Karnataka is the one and only bastion in South they can hope to conquer and retain if the Party plays its cards well.
Other parties too in Karnataka are yet to get their act right. That's a boon for BJP. Congress and Janata Dal (S) are having their own problems and it takes them time to sort their home before they can pose any real challenge to the BJP. This in a way a blessing in disguise for BJP and the Party can use the remaining two years of its term to run a clean and good government. Such an achievement will establish BJP emphatically in Karnataka and most importantly may well bid adieu to Deve Gowda and Sons. While people of Karnataka wait for good government BJP too must hope to get its act perfect this time round.