I remember the old IC-22S rigs, with diode programmable channels.
And I still have (and use) an IC-27 and a couple IC-28s (1986 or so?),
which work fine except that they only permit the programming of 3
subaudible tones at a time (and you need the magic decoder sheet).
But beyond having the tones conveniently programmable for each
channel by tone frequency, rather than some numeric code, I don't
see a lot of improvement in basic functionality in newer rigs that
would justify an upgrade.
Yes, a lot of rigs are now dual band, which might be an argument
if you have 70cm operation of interest in your area. (I rarely use it.)
We got an IC-207 (1998?) for my wife because we needed a remote
control head to fit it in her car, and at the time they were only available
in dual-band radios at the time. (That is now my primary radio at home.)
I have a dual-receive radio in my car because I needed to monitor two
frequencies simultaneously for a particular application. (Otherwise, the
scan function would be adequate.)
Some of the digital radio fads have come and gone, without
making a particular impact around here (other than leaving
folks with expensive radios whose features they rarely use).
So there are some newer features that might be useful in specific
circumstances, but I don't know of any major enhancements to
functionality in the last 30 years or so that really has made an
improvement in talking on the radio. (There may be some areas
that have shifted to narrower channel spacing, in which case
you would want to make sure your radio was compatible.)
And I still program all my radios manually, although most newer
ones have the option to program via computer. That might be
useful if you are programming 100 memory channels at a time,
but I don't talk on that many frequencies.