Uh? Why do you miss that? N900 has it...

As for me, I only miss two things:
- T9 texting (which is almost there... just a little bit more and it's done!)
- Built in smart RFID (6230 had it)

The later I can almost do with a dumb RFID card by hiding it under the case... but it's not as adaptable as the smart RFID built into the 6230. :P

Over all though, I don't miss either enough to go back to the 6230, or any other device. The N900 does so much more that going back would be like ditching a DeLorean (with flux capacitor) for a yugo.