Man, do I hope that Hero Factory will have a decent storyline. I hope it won't be as bad as Slizer's (Bionicles Primal Ancestor) was... This was Slizer's complete (emphasis on COMPLETE) storyline:

The planet that the Slizers/Throwbots lived on was called Planet Slizer/the Throwbot Planet. The planet was divided into 8 continents, seven of them dividing the planet into seven sectors. The eighth and smallest continent, on one of the hemispheres where the seven other continents converged, was the Judge/Jet Continent. It was the stadium for Slizer/Throwbot competitions. The Slizers/Throwbots trained for the competitions by fighting the natural adversaries that existed on their continents, but perhaps Judge/Jet did not because he seemed to have no natural enemies in his continent. Also, when not competing, the Slizers/Throwbots were divided into two factions of “good” and “evil”. The “good” side was made up of Fire/Torch, Ice/Ski, City/Turbo, and Sub/Scuba, while the “evil” side was made up of Judge/Jet, Jungle/Amazon, Rock/Granite, and Energy/Electro. These two factions fought each other constantly when not competing in the stadium, and it is unknown whether belonging to either of these two factions interfered with their stadium competitions.

-BioHazard96 - Biomaniac

Another Side... Some people hope that HF will have a terrible storyline, that way it'll die quicker, and get replaced with something else, better...

For those who are looking for more info on the Slizers, look 'ere!!!
Official Slizers/Throwbots Topic