To be fair, Lindsay only got... what, 2 episodes? We're talking Adam-level companion here. But you have a great point.
That does bring up the age old question of who was the best companion for Hurt. As you say, Lindsay only got 2 episodes, well 3 (and a lizard). Claire McCrimmon, on the other hand, was around a good long while, all things considered, and had a great impact on the show. Back then a lot of people derided her for simply being a "second-generation" knockoff character, but I don't think those folks really understood what was going on. Much like Frobisher.
It was good to see a couple of actual alien
companions again, though, too.