Don't forget my tips tip. Order those yellow foamies now, don't waste a moment. The difference is NOT subtle. In fact, I'll wager it makes more of a difference than re-encoding your files, at least in regards to the nature of your specific complaints.
Of course, re-encoding should help too. I listen mostly to lossless, so I don't have extensive experience switching between encoding levels. But I do have limited experience, and I can tell you that, in listening to my lossless versus 128kbps ACC files that the tips make a bigger difference. Yes, the lossless files have much better detail and timbre and depth to work with. And upgrading your encoding level will probably be an important part to your overall sound goal. But I don't think it'll be your main part. It doesn't have as much to do with clearing up the overcoloring of the bass, which washes everything out, and which is your primary complaint if I understand you correctly.
Let me give you an example. It's like looking at two paintings... one is a watercolor (olive tips), where every object in the painting is blending into everything else. And the painter didn't dip his brush between colors, so the darker hues (bass) kinda get painted onto everything else and overpower the lighter, more delicate colors. The result is not always displeasing, btw. Now consider the other painting (yellow tips). The objects in the other painting all have a bold outline around themselves, so everything is highly defined. All the coloring is between the lines. The colors are more vibrant. Everything is kept its respective place, restricted yes, but the overall power of the image is not lost in the slightest. Rather, it's just better communicated. Everything... every...thing... ev..ery..thiiiiiiiiiiinnnng.... in it's right place. In it's right place. In it's right place.
I find the most noticeable difference using yellow tips in the drums/beats. The impact is stronger, with more kick. It actually kinda tickles my brain. But most importantly, as a result of reigning in the bass, everything else has a chance to shine. The mids resolve better, the highs are more present, the sound itself seems to have more texture. It's like lifting a heavy curtain off a loudspeaker.