I want a bigger soundstage, more clarity, more bass and better treble as well. Unfortunately, I can't go into details, since the various terms used for describing IEM sound are puzzling to me. Seems I need a personal audio trainer and some good gear to get to the bottom of this.
Can you make any recommendations based on these requirements?
If you're coming from an ES5, and you want more of everything, it's best that you seek out users who have used/owned both. Nevertheless, from my (our) perspective, the K10 is damn near perfect, offering a good serving of prominent but controlled bass and treble, and a sweet mid-range to die for. If you ask me, the K10 is good for a myriad genres, and is best described as an expert jack-of-all-trades. With that said, the market is big, so take your time to look around, and audition them, if you can - your ears are your best guide.
In short, if you want a good all-rounder, the K10 should be at the top of your shopping list.