I actually think a lot of the mechanical streamlining in RE5 actually diminishes the tension that 4's combat is so suited at creating. Everything from little things like being able to reload in the menus, to being able to quickly dispatch downed enemies with another invincible melee attack instead of opening yourself up by rushing in to knife takes away a little from the tension of the enemies getting ever closer. I did like the realtime menu a lot though, and quick weapon swapping was pretty great. As far as better enemies I think 4 tops it still. In addition to having way better bosses you have more creative enemies like the garador, a more challenging chainsaw man than the one in 5, and in my opinion much more fun and challenging varieties of the base enemies (better AI, more interesting designs) and are used in conjunction with the level design way better (take my sniping set piece comparison for example). 5 also had the terrible descisison of having regular majini with laser sighted assault rifles rather than a rare chain gun guy, which turns a big chunk of the game into an awkward cover shooter. I like the tribal majini a lot though, they add interesting tweaks to the combat (harder to ground melee, long spears, jump inning, etc).
Yeah the two el gigante fight isn't too hard because you can take one out instantly with the lava
Pit, it's just notable because the game throws two of those fuckers at you like its nothing, and it's just one of the cool curve balls the game throws at you surrounded by a bunch of other surprising and memorable encounters. The water room is definitely a highlight in terms of challenging encounter design, and Ashley makes it better by just adding another layer of tension as you have to watch out for her and consider your movements and enemy priority even more.
I haven't gotten to the jetski part yet so I'm not sure how I'll feel about it this time around, but I don't remember it being too bad. The thing is 6 has like 4 or 5 vehicle sections and some of them are pretty long, and they're all really fast but when you try turning it suddenly feels like you're going through molasses.
I was saying that I fought both of them without the floor trap. It's funny you call that a curve ball, when by most definitions it would be called a "difficulty spike" (mainly the water room since doing what I did is more like an extra challenge) and described not nearly as celebratory. I just happen to be one of those people who like difficulty spikes though.
Dr. Salvador is definitely not more challenging or threatening than the Chainsaw (or Executioner) Majini. He's is 100% helpless against the shotgun. This is one case I'll point to where the difference is clear. Garrador is one enemy I miss though.
On that matter, I think your description of the village encounter above is little too romanticized (as it always by people). Here is how the village works, really, assuming you are not aiming for style points here. You get the item from the first house on the left, ideally not arousing suspicious until after jumping out the window into the alley. Run around that path (and maybe up the tower and behind the farm) picking up items like herbs or more grenades and ammo; the threat level is rather low, but you have to learn how to walk passed enemies to try to grab everything. Then you go into the shotgun house (spawns Dr. Salvador), clean up the items there. Then you get on the balcony and loop around to the dead-end. Then you sit there killing everything (or temporarily disable for maximum AoE damage) that walks in front of you, using the shotgun so that Dr. Salvador can't even get close to you. Then it's time for bingo, the end, videogame's most cherished setpiece. In my opinion, the village doesn't compare favorably to the water room or the double Garrador room or playing The Mercenaries. The public assembly from RE5 is better in most ways.
RE5 gun-wielders were most awkward (but surprisingly ineffective) during the spinning platform scene (cover is nonexistent), where it isn't even worth engaging them because it's a bitch to aim, but the rest weren't that bad. I admit, the first time I had more issue with them, but this time I barely used the cover system, opting to just hide behind objects instead and quickly dispose of them (also I don't see how seeing their laser sights is a bad thing, if that's the implication). In the end, they are not really that ubiquitous. I think I actually had of an more issue with the last two (out of three) heavy machine gun appearance guy in RE4 because of the layout (and perhaps my reluctance to use magnum ammo to trivialize it).
The problem with the jet ski part is the combination of falling rocks and you having to speed up, so you running into them as they are falling in a way that doesn't immediately tell you where it is going to land (the visual is a big mess of debris). If you are using retries then it is a minor trial-and-errror issue in the final 30 seconds of the game, but because of save placements it was rather frustrating having to redo the final boss as I was learning/relearning this.
Anyway, I've talked enough ill about RE4 in this topic and don't really want to tackle any more romanticized descriptions, because I love the game. (Maybe shouldn't even said what I said, but it was funny that I did the same thing in terms of playing RE4 and RE5)
EDIT: So I can be laughed at, here are the ways I died during the jet ski section (meaning I had to fight the whole final boss again each time)
-A rock, better not hit that. DEAD. Oh fuck, it was a ramp I had to hit.
-Man, I'm moving really fast - and that's a lot of shit falling everywh- DEAD. Wait, I think there was a rock inside that?
-Alright, I'll slow down a little bit just before it falls. DEAD. Oh fuck, the water.
I think I died one more time, but I forgot how, pretty sure it was related to the debris.
I actually have two questions on the RE4 that bugged me while playing it: Is there a list of enemy respawns (like going back to areas you don't need to and finding enemies there) and what exactly drops the dynamic difficulty other than dying?