Not to be contrarian, but just to share a differing opinion: I played Scholar before Vanilla (i wrote of DS2 due to GAF's feedback on it, but later decided to give it a go with the PS4 version) and really enjoy the Iron Keep. It feels like the enemies are spaced out just enough so you can deal with each one before having to deal with the next, though you definitely have to use range to your advantage to occasionally pull and watch out for the archer bolts coming in, it became quite exhilarating and its one of my fav areas on repeat playthroughs. Though its not an area you can effectively run through, you're quite right.There's waaaay more Alonne Knights in the first large area and as you say, they all aggro from miles away. If you decide to go for Smelter Demon it just makes it an astonishing slog retrying it if you die. It was aggravating even with a few playthroughs of DS2 under my belt and only dying a couple of times to the guy, I can't imagine how annoyed I'd have been if I'd never played vanilla.