Well, since I'm the one responsible for the Elephant units, I'm going to state exactly why they are at the strength they are and why I'm not going to change them.
- Elephants need to be strong because that is really the only thing they are capable of. Elephants cannot move speed 2 (like horse cavalry), get defensive bonuses (for mounted units, that's restricted to the mobile defense line), or bombard city defenses, so that leaves attack strength as the one thing they need to have, or there is no point in building them at all.
- Likewise, Elephants need to have a good strength to stay relevant throughout their lifespan. I originally had Elephant Bombardiers at Strength 20 so they would have a chance against Musketmen. I was convinced that was too strong and lowered them to 16.
- Pikes are the wrong counter unit for the Elephant Bombardier, and in fact for any gunpowder cavalry. I think tech diffusion is doing an excellent job of keeping tech equalized across all players, so by the time some players get Gunpowder, it spreads to everyone, and Matchlock is only one tech away (the other prerequisite for Matchlock is Clockworks, which is a Medieval Era tech and pretty cheap by the Renaissance).
- I don't think it is necessarily a bad thing to occasionally have the pendulum swing back and forth between attack and defense. The early eras have it very hard to rush another player; my usual early wars start once I get Siege Warfare and Smithing and can build/upgrade Swordsmen and Catapults. Then the pendulum swings back to defense once the AIs get Feudalism and Longbows, swinging back to attack again once I get Armor Crafting and Heavy Swordsmen, but not nearly as far.
- Also, I think that having some "sticks" to occasionally prod the player towards military techs is a good thing as well. It's hard to weave some of the techs on the tree together as tightly as I would like without being heavy-handed about it, so it doesn't bother me to give players some reason to stay equalized across the columns instead of beelining down a row.
One thing that I do want to do, and I've mentioned this once before, is to kick down the requirements for Formation/Charge/Ambush promotions from requiring Combat or Drill II to just Combat or Drill I. This would allow getting anti-mounted Arquebusiers faster.