Halo is not a bad game, you seem to forget when it came out it smashed sales records
There's a reason it's called gaylo.
But anyway I liked halo SP and I would argue that it's a significantly influential game in the history of gaming. However, the point is that Quake being second only to Doom in the history of the most influential games, modding quake into halo is like modding The Legend of Zelda into Kid Icarus.