Better is relative. Both the RE252 and RE262 are quite good. The RE252 has more bottom end and top end presence than the RE262, but the RE262 has more effortless dynamics, has a driver that is more refined, and does end up with punchier higher frequency bass with subtle bottom end presence. Treble on the RE262 isn't bad, but also helps if you remove the foam and stay away from any foam tips to show more through. The top end is more subtle on the RE262, but it's there and quietly sparkly
. I am liking the driver used in the RE262 more than the RE252. The RE252 is more balanced in response though, so it works nice with more music, but the RE262 has a better sound stage, more dyanmics, and is cleaner. The RE262 tends to show its color from time to time with the wrong music and certain things just sound off.
It just sounds like you're looking for something totally different than either. You seem to want both ends emphasized more, so you should be looking at products that specifically do that like the Triple.Fi 10 or Westone 3. For as uncolored as you think you want, maybe you really aren't looking for a lack of coloration after all. It's tough to say. You may simply want something a little better or you do want specifically emphasized bass and treble. It's really not wrong either way. You just have to know what you like and use hardware that fits that.
On a side note away from the HifiMan line, I would also point you to the e-Q7. This is a really well balanced earphone with excellent extension but also the moving armature design has a more dynamic driver presence which gives it a good visceral presentation. It's more balanced than the RE262, not quite so lean on the bottom end, and is more dynamic and effortless than the RE252. I've kind of come to consider it the best all-around balanced earphone out there. I think the RE262 has a really stellar driver, but it's hard to ignore the coloration regardless of how subtle/tasteful it may be. EQing of course works to modify it as desired, but you have to have an EQ available for it. From a balance standpoint, the only other earphone I am really fond of is the CK100, but it's hard to get affordably. The CK100 I kind of see as the pinnacle of balance and refinement of presentation. It has more bottom end than the e-Q7, a more refined top end, and a more pinpoint and laid out sound stage, but it's less visceral and doesn't quite pull you into the music like the e-Q7 does. The e-Q7 has a better sense that you are there, and the CK100 is more like you're watching it. Plus the price of the CK100 is a heck of a lot more. It sort of ends up that the e-Q7 is an outstanding buy for the sub $300 (used, or eQ5 new, same driver) market. The CK100 costs more but doesn't really give you holistically better, simply something different.
