Huh, I'm surprised you didn't like RE5. I love it as a single-player game and adore it as a co-op experience. Many fond memories, i.e. the executioner fighter, the chainsaw baddie in the streets, the tentacle monster in the incinerator, the motorcycle majini, exploring the swamps in the hovercraft, the mirror ruins, the lickers in the lab, U-8 on the elevator, the flamethrower fight, 2v2 against Wesker and Jill, curing Jill, the orbital laser fight, the Wesker-catching-rockets fight, "complete global saturation," punching the boulder, etc. Game is a gosh darn classic, and still looks visually insane to this day.
RE6 is also fantastic once you acclimate to the controls. From a combat and mobility standpoint, it's the best third-person shooter/brawler on the market, eclipsing Vanquish. Mercenaries throws such an insane variety of monsters at you too, and they have so many mix-and-match transformations, i.e. you can have a baddie who grows a parasite head, matched with a shield arm, matched with grasshopper legs, etc, forcing you to roll-dodge away from jumps while circling around to his rear.
I dunno, I really suggest giving these games another chance with an open mind. The beauty of the RE Action Trilogy (as I like to call it) is that each offers its own unique experience with its own distinct atmosphere. RE4 is more a slow burn with methodical pacing while RE6 vacillates between quiet atmospherics (the college campus, etc) and balls-to-the-wall action, and RE5 is somewhere in between, but they each have something special to offer once you realize everything they allow you to do.
