I'm really skeptical about complaints regarding Shep saving Liara. LOTSB was always advertised as Liara-centric. You paid $10 to spend more time with Liara. This is her story. The desk throw is a dramatic contrivance to remove the less relevant squad member and says nothing about anyone's competence or how much they care about the third squad mate.
Of course! The name of the DLC is a typo! It's supposed to say 'Liara and the Shadow Broker'! Our mistake this whole time! I can see how that got confused.
Really, though, for all that the squadmate is there, the overall impression in LotSB is that they AREN'T, that this is Shepard and Liara on a solo mission. Hell, there's some dialogue in 3 that feels like that's how it's meant to be remembered as, that it's implied that it happened with just the two of them waging a private war, without Shepard's squadmate coming along. While I understand the practicalities of getting twelve VA's into a recording studio to play bit parts, 'dramatic contrivance' is only a production answer to that, not a story answer. In the story, if Liara was not romanced and an ME2 squadmate accompanying them was, why would Shepard move to protect Liara first if their romance is there with them? Just because she's physically closer would not make protecting her their first priority. If something has to be answered through production reasons, rather than story reasons, then it's a flaw of the story.
Not to mention, this particular 'dramatic contrivance' is a bad one. There are also other possible solutions for why the other squadmate wouldn't be in the fight - place Shepard and Liara on a platform that drops them down into the Shadow Broker's lair, for example, or perhaps an ambush of Broker agents that Shepard orders the other squadmate to hold off as s/he follows Liara into the lair. The Broker obviously has tech all over the place and kinetic barriers of various strengths are already part of the lore, having one activate behind Shepard and Liara would have split them off from the squadmate just as easily. There are ways to handle it that were not 'Shepard's other squadmate, friend, and potential LI lies unconscious on the ground for several minutes during the climactic finale being all about Shepard and Liara.' Instead, it was decided to have Shepard knock Liara out of the way and just knock out and ignore the squadmate. It's like BioWare forgot that there were people who liked the characters of ME2, cared about them enough to want to have them along when they go on missions, a strange thing, considering that was something of the point of ME2, forging a connection with these characters.