Khmer as a civ has gone though its paces. From an underperformer with quirky bonuses and strong elephants, it has become a knight spam civ with probably the best farming bonus for early game beating even the slavs. Though these changes have made the civilization versatile. The last patch benefitting scorpions with ballistics has pushed it to an extreme. Added to that the buffs to elephants have given the civ an even better DPS option than knights and cavalier. I believe its time the civ shed some of the extra fat, it has gained overtime and made into a leaner tech tree focussing on Elephants and Siege.
First change:
Battle Elephants move 10% faster -> Battle Elephants move 20% faster.
Remove - 'Husbandry' from tech tree
Tusk Swords: Battle Elephants +3 attack -> Battle Elephants +5 melee attack and +2 attack bonus for buildings
Remove - 'Blast Furnace' from tech tree
Remove - 'Arson' from tech tree
This first change is to make the best elephant civ actually make elephants in place of heavy cavalry by making the unit more scaleable throughout castle age despite the cost. Battle elephant can also work like a siege elephant with the bonus against buildings.
Second change - Team Bonus
Scorpions have +1 range -> Elephant units have +2 LOS
The LOS will be double of knights making them as good as ranged units vision wise to patrol the map.
Last change
Change - Remove the 5% slower workrate of farms.
Remove - 'Bloodlines' from tech tree
The 5% slower farms is meant to disrupt scout rush potential. Removing Bloodlines will do exactly the same. Battle Elephants gain just 8% HP boost from bloodlines. Their stats are not going to be affected much by losing ‘bloodlines’. With farm nerf gone, Khmer can easily tech into elephant in castle age despite the food cost being higher.
Optional change:
Remove - ‘Cavlary archer’ from tech tree
Add - ‘Elephant archers’ with elite upgrade to tech tree with the movement speed bonus being shared with them.
Though I admit, ‘Elephant archers’ are still not a properly designed unit. Khmer can definitely make them work in castle age.