Seven and The Doctor were like Eddie Murphy and Joe Piscopo on Saturday Night Live in the early 80s. I suppose there are folks who think those guys were overused but they were the best talent the show had at the time and the SNL probably wouldn't have survived without them.
Same with Seven and the Doctor. I'm glad the writers and producers turned them loose in seasons 4-7. Others may not agree but I believe it kept Voyager relevant and prevented it from going the way of Enterprise.
No doubting Picardo's acting talent but Jeri Ryan's "talents" were somewhere other than in her acting range imo.
Picardo carried that double act but Ryan's "talents" certainly attracted a certain market to voyager.
Didn't make for the most compulsive viewing though imo, and served to re-affirm certain steriotypes about the fanbase.