Improvement number one is one that will either have you grinning surreptitiously in delight, or completely nonplussed - we sit on the former side of the fence. This is because while the SE535 earphones are available in the tastefully elegant metallic bronze finish sported by the SE530 before them, they're also available in a clear plastic finish, which looks absolutely fantastic. Maybe it’s our inner geek speaking, but there's something fundamentally cool about being able to see the internals of a high-end piece of audio equipment - or any item of consumer electronics for that matter.
Improvement number two may prove even more divisive of opinion. As ever, Shure employs an over-the-ear cable design, which helps reduce cable microphonics (that is, brushing noises). The SE535 now has a length of formable wire where the cable meets the driver unit. It takes a bit of time to get used to this stiffness, and in fact the entire Kevlar-reinforced cable is tougher than the SE530s' was, but it does help keep the fit secure if you're moving around a lot.
Those that do find themselves longing for a more flexible (pun apologetically intended) wiring option shouldn't despair. The most interesting feature of the SE535s is found right at the point where the cable joins the drivers. Instead of the wiring being directly attached, inside these units, Shure has implemented a lock-snap MMCX connector. This is free to rotate, so there's little chance of it disconnecting unintentionally, and the other benefit is obvious. If, providence forbid, you somehow break the wiring of your SE535's you'll be able to buy a new length of cable - which is definitely cheaper than replacing the entire set of earphones. Similarly, it's entirely possible that Shure might offer cable lengths with in-line remotes or thinner wiring to suit different customers' needs. In an ideal world we'd all buy custom-made earphones designed exactly to the specification we want anyway, but as the world is far from ideal this is an excellent step further from Shure towards making universal-fit earphones truly universal.
The SE535's driver units have been overhauled, too. They are now a little flatter, and generally just smaller, so they fit into the ear that bit better. If you happen to wear earphones while in bed that will be a particularly useful as you can wear the SE535 earphones without having your pillow shove the 'phones through your eardrum. Not that a more comfortable fit isn't an improvement in every other situation as well.