I don't think it's fair to blame Lori for how different the show is now. Season 1 had CIA girl there for a while and that didn't impact the dynamic very much.
The show itself has changed. As has been pointed out in this thread the type of investigations are different this year. Last year it was terrorists and other super villains. The show would start with an explosion or gun battle. There would be a car chase and then the team (well Steve) would beat up a guy (while Danny pointed out Police procedure) and he'd give them the location of the evil lair, failing that Chin would Bing "Villain secret hide out" so they'd know where the baddies were.
Then it would be burst in guns blasing, Kono (a week out of the academy with a dodgy knee) would kung fu a group of thugs using her 5-0 power up. Most baddies would die, leaving one for Steve to say "Book em Danno" for.
This year it's a regular murder leaving trace evidence, interviewing a bunch of people, following the clues leading to a confession and arrest. It's a lot more like other cop shows now, CSI, NCIS and so on. All this following clues and interviewing suspects is what's taking up the screen time that you think should be filled with Steve and Danny playing volley ball topless while bickering about which house mate should be evicted from BB that week.