I’ve won games with dravidian elephant archers. They are much better in late game than skirms are (though getting the gold for the elephant archers can be an issue). Dravidian skirms are top-tier, but they are still a trash unit - spammable in late game, useful as a counter unit, but otherwise lacking in power.
HP regen on elephants is useful: it means that they’re practically immune to chip damage. Some examples from my own experience - a mass of elephant archers tank a mangonel shot. With hp regen, they’ll all start regenerating (with 10 elephant archers, that’s 300 hp/minute. And it could easily be more than 10 elephants). Without it, the injury is basically permanent (unless you spend a prolonged time under monk healing, which is often a significant loss of momentum and requires fragile/gold-heavy monks). Another example: pushing underneath an enemy castle against defending skirms. The opponent could focus fire with the skirms, but as it’s post imp, they might not be able to afford the action economy. And the castle likely won’t be focusing on the same unit as the skirms, which results in additional healing. And while Skirms counter elephant archers, elephant archers still trade pop-effectively against them (even under a hostile castle), and pushing underneath the castle allows you to forcibly stop repairs or destroy enemy BBCs (making it much easier to take the castle down).
Elephant archers require 70 gold per unit (soon to be 80). Medical Corps requires 200 gold. It basically only needs to heal 3 (soon to be 2.5) elephant archers worth of hp to be worthwhile. With elite upgrade, that’s 840 (soon 700) hp - less than 3 in-game minutes if you have 10 injured elite elephant archers. And a post-imp elephant archer mass should have much more than 10 elephants.
The basic point is, with medical corps, I feel a lot more comfortable pushing with dravidian elephant archers. There are still things to watch out for (a mass of mangonels would be enough to justify a retreat until I can snipe them with BBCs), but I can take fights that would otherwise not be cost effective because I know the elephant archers will survive and heal afterwards. And the tech isn’t all that expensive either.
Dravidians, Bengalis, and Burmese are all elephant civs (and Dravidians and Burmese are both also infantry civs). Armenians are a DLC civ. Gurjaras are another elephant civ (one with a weird start/playstyle). Romans are a DLC civ. Koreans are the first civ here that are neither an elephant civ nor a DLC civ, and Koreans don’t have a power problem (they’re really strong in their niche). Meanwhile on the other side, the most popular civs are (in order right now) Mongols, Franks, Magyars, Persians, Khmer, Spanish, Huns. All civs that have a strong scout rush and great cavalry options (even after excluding elephants).
I’ll also note that I’m about 1000 ELO (with an eapm around 20), and that I do find the wood bonus to be quite useful. 1000 ELO is close to the point where build orders become somewhat mandatory. In my opinion, if a player has enough skill to get gold on the early eco art of war, they have enough skill to use the wood bonus effectively. It’s rather easy to use it to pay for a stables/archery range/blacksmith or even just some extra farms. And even easier on water maps.