Sure. My S4i is about to give up, left earpiece is about 10% of the right in volume.
But generally, The S4i and the GR07 CE aren't terribly different in terms of overall balance.
The GR07 CE to me is a bit flatter, the S4i feels a bit more emphesized in the higher treble, where the GR07 has a bit more body.
However the GR07 has more lively, rippling detail over the entire spectrum, and it is more aggressively textured, it really puts small nuances very in your face, it's extremely effortless to listen to, even in dense action scenes with rumbling and music a small sound of a gun clanking against a surface will snap at you with excellent speed and transparency. Some headphones, when you turn them up in volume, you feel like the diaphragm, as it needs to move longer distances to produce louder sounds, struggles to be as articulate as it might be at lower volumes due to it working against it's own movement (like if you imagine yourself drumming on a snare drum at 5 beats per second. If you lift the drum stick very little you can achieve those 5 beats at a low volume, but if someone asked you to play louder, you'd need to move the stick higher and strike harder for each beat, meaning you may only have time for 4 beats due to having to do more work, and with the faster arm movement you also need more time to actually change the movement direction of your arm as you strike and lift the stick.
The GR07 is more crisp in texture, while the S4i is a bit brighter, but not as crackly and detailed in that sense. The S4i has a pretty good sense of detail though thanks to the brightness, but it's a bit behind the GR07.
Also the treble of the S4i feels a bit "broken" in a sense. You feel almost like some narrow frequency bands in the treble are missing (doing a sine sweep shows that the response is reasonable and continuous though). It feels a bit like there is some "ringing" there, i.e. some treble frequencies seem to be there even when the music/sound doesn't emphesize them.
An overall difference is also that the GR07 is just a more dynamic headphone, gunshots really snap from treble to bass, where as the S4i is quite laid back and the treble has to do most of the work of supplying a sense of detail, and while fairly dynamic and lively, doesn't have the speed and cohesion that the GR07 does, the GR07 feels like it works as a single headphone, where as some parts of the S4is range feel a bit lazy or uninterested.
This is with stock tips for both the GR07 and S4i. Also the S4i is ready for the bin, so I can't really judge the stereo width or how well it conveys l reverb or echo or other minute details like that.