I voted yes...reason being is that SST is almost into year #2 of it's life cycle. The two original races have been fleshed out to such a degree that there are enough units out there to allow a player to focus exclusively on just one race...meaning, even as good a deal as it is, the boxed set might not appeal to someone ONLY wanting Bugs or MI.
I will say that including a tanker instead of the blisters/blasters (and raising the price if need be) would probably sell more army boxes. The visual impact of the tanker is not to be underestimated. Also, that particular box set would open the door to cross-over sales to fans of the SST movie just looking for models (since all 3 unit types: hoppers, tanker, warriors are from the movie)...which might even lead to a few more folks getting into SST: the Minis Game.
Yes! This is a great idea to get folks into the game, especially when you think about the points difference that comes with the starter set. Now a starter and an Arachnid boxed army would provide enough points to balance things out!