Paramount wanted ratings equal to what TNG got, however Voyager running for a full seven years shows the ratings held steady enough. The soultion to the rating issue wasn't the Hirogen but rather the Borg which proved a boost in viewership every episode they showed up in to spite the online back lash they get now.
Many of the ratings issues Voyager had was due to the audience being divided because DS9 & Voy in many major cities ran side by side on totally different networks, causing the audience to choose only one. In many major cities Voy. was allso never aired, a a portion of the audience never saw it during it's original run.
It goes without saying that Berman and Braga thought the Borg were the magical solution to every series since TNG [save DS9 but they didn't exec produce that series].