I don't there would be too much of confusion. It would not mislead people except some remote areas were people still would believe the words of the netas and the false promises would get them votes. The whole exercise, the campaigns, the extra manpower, resources all can be reduced. The issues of mixing up issues will be remote, For instance the people of Karnataka have a unique set of issues that we are all familiar with but lack detailed knowledge about issues in neighboring states. Similarly all of us would be knowing about the national issues. The only potential issue would be if the central and state governments are of different parties and both parties are wooing voters for the state and center, there's bound to be some tense moments or clashes. Would there be an legal issues or constitutional statues that need to be kept in mind? May be it needs all-party approval and then the EC can make arrangements.