Ignoring the fact that pharmaceutical companies are inexplicably creating Bio Organic Weapons, giving the zombie-esque dudes guns was only ridiculous to me because the gameplay didn't evolve enough/at all to make them work. In RE4, enemies were created around the additions and limitations of the gameplay. They were given axes and other melee weapons, but not guns because players didn't have the mobility to accommodate gun wielding bad guys (besides the slow Gatling gun quasi-mini-boss). In RE5, players still didn't and were barely bailed out by the fact that there were now 2 of you. While I liked RE5, it didn't really work as a single player game anymore and the co-op wasn't good enough to effectively ruin the single player experience.
Revelaitons did a good job of altering the gameplay enough to accommodate the more-zombie-like Ooze. Despite its relatively minor flaws, it had come closest to reconciling pre and post RE4 gameplay. Still, I think the series is really missing Shinji Mikami's direction and game design expertise.
From what I've read about RE6, excessive QTEs and mish-mash of ideas are the major strikes against it. Plot and dialog are also apparently still laughable, but I feel like that's part of the charm of the series. Killing of the series main villain in RE5 did kind of paint Capcom into a corner. Where does this leave Chris? I'm sure RE6 seeks to answer that one, but killing him off would change the series. It would give the impression that no one is safe and that the development team is willing to go all out though it still starts with the gameplay.