For one thing, garage door opener crime security has improved quite a bit over the last decade. Older openers had a fixed code and enterprising thieves could rig a remote to exploit vulnerabilities in that code. Nowadays, garage door openers have what is called a rolling code which encrypts the code every time you use it.
One long time problem has been what happens if there is an electrical outage in your area, or you have blown a fuse. Newer garage openers how have a battery pack as a backup for such emergencies.
If you have an old garage door opener, chances are it’s pretty loud. Most of the time this is not a problem, but if someone is trying to sleep in on the weekend, a loud opener can really louse up the day. Older openers were loud because they used a noisy chain as a drive. Newer openers have belts or big screw drives that make almost no noise because they have no moving parts.
Keypads are another feature that is not common on old openers. Keypads are mounted outside the door and allow you to open without a remote, and it can be pretty handy. It is technically possible to buy a pad by itself, but if your door is that old it may be time to upgrade anyway.
Perhaps the most important feature added in the last 20 years is the auto-reversal mechanism that is mandatory for all openers. Essentially if something is in the way of the door closing, the door will reverse itself. You don’t want to be caught underneath a 200 pound garage door.