Indiana Senator Mike Delph from District 29 has introduced Senate Bill 146 which would remove the option of straight party ticket voting from Indiana election ballots. As Doug Masson notes, this change would probably favor the Republican party in most districts.
I think straight party ticket ballots generally only do a disservice to Indiana voters.
At best, it enables a kind of impulsive loyalty to a vague label that can mean very different things to different people.
At worst, it facilitates voter ignorance, allowing good candidates to be glossed over while other candidates are voted in based on affiliation instead of qualification. (I was surprised in my own limited experience as a candidate how many people in Richmond said they thought I was probably a better person for the job than some of those running in their own party, but wouldn't vote for me because of my party affiliation on the ballot.) And as Doug mentions, political parties aren't a concept that the state or federal Constitutions help us navigate very well, so baking them into our electoral process doesn't seem quite right.
If someone wants to vote only for candidates of a particular political party, that's fine, but let it be because they've researched who those candidates are and what they stand for, and then made their choices well in advance of election day. And if this change to election law hurts Democrats because Democrats were winning on party loyalty alone, then so be it; that's a problem for the party and its candidates to take up with voters.