Yeah - and I get the impression that 5.0 isn't anything like 4.0, so maybe it wouldn't be as unpleasant as I've been fearing. I had been with two very long-lasting gaming groups (~35 years each) which both dissolved in the last couple of years, so maybe it's time to modernize.

D&D 5e basically acts like 4th Edition never existed, and you will find it very familiar as someone who ahs played 3rd Edition.

Mechanically at its core, 5e is has a very close similarity to 4e with encounter powers becoming recharge on short or long rest and daily powers becoming recharge on long rest, and a few similar translations; it's much closer to 4e in that regard than to any earlier edition. And the catalog of classes, and other options, and their design doesn't throw out 4e heritage entirely, either.

But it manages to avoid, IMO, the super-metagamey feel of 4e.

I get where you're coming from here, but the basic crunch of it is delivered on a 3rd Edition base. If you look at a 4th Edition Wizard, they have at-will, encounter and daily powers, just like any other 4e class. If you look at a 5th Edition wizard, they have... spells, broken down by spell level, in a way that feels very familiar to 3rd Edition players. Some of the spells feel like they haven't changed at all from 3rd Edition.

Here's 3.5th Edition magic missile: https://www.d20srd.org/srd/spells/magicMissile.htm

Here's the same spell in 5th Edition: http://5e.d20srd.org/srd/spells/magicMissile.htm

Very similar. The 5th Edition version is a bit simpler to read/understand, but frankly if you sit there at the table and think you're casting the 3rd Edition magic missile you will get it right 8 times out of 10.

And then on page 20 of this quickstart rules, you can see the 4e magic missile, which is a very different spell altogether: https://issuu.com/biggerstaffhosting/docs/quickstartrules