I've considerable experience with 4E minions, hordes as swarms, and 13th Age style roll-over damage mechanics. I like them all, but they have their own uses. 13th Age style is probably the most useful since it's an easy to remember rule that can be applied as needed. Kit-bashing monsters is relatively painless in 5E, but you don't generally want to be improving it when the group goes off the rails chasing gobo raiders when you expected them to take on the wizard's tower.
Hordes as swarms are useful IF you're dealing with hordes and mass combat situations. Given them area of effect attacks is the way to go as originally suggested. They also work great as allied units or cohorts under PC control. "All right, men, onward to glory!"
4E minions work best for filling out an encounter with a smattering of troops that complicate the tactical situation. They serve as mobile roadblocks, harry the back line, dash off for reinforcements, or even do cool stuff like explode or turn into pools of deadly acid when killed.
Most of these uses can be served by existed low-level baddies. If you want to add more to an encounter make their hp 1 and drop their static damage by a few points and put in two or three times as many.
In 4E I loved giving minions abilities that activated with combat advantage (like double damage, debuffs or automatic damage). It really made them dangerous in swarms or with clever positioning. The party was encouraged to deal with them before they could get into flanks. Made things tense and heroic at the same time.
For 5E, with the advantage mechanics at play, I'd probably just give them automatic hits or double damage (without attack advantage) on a hit as a general rule. One of the best things about minions as a DM is resolving their turns quickly with little or no thought. Rolling fistfuls of d20s kinda ruins the point.