Yes, the bonus would be fairly balanced. Ranged units will be more powerful. But the cost will make it a pretty defensive play. It would also make their towers and castles more capable which @Pulikesi25 was refering to. The civ could play to boom with defensive structures as well instead of being too aggressive as they currently do. It gives balanced options to the civ.
I undestand that which is why I had suggested the team bonus of giving +1 pop space for every building except walls and gates.
The bonus in itself is not OP. Its benefits are less than Wu’s “Houses built 2x faster”. But it allows Dravidians and allies to train an unit immediately after making a building then make a house if more production is needed. It is useful on both land and water. Current Dravidian bonuses are too focussed on water play which is ruining the civ design making it unpopular since water maps are not popular. Dravidians should be capable of playing arabia like Malay or Vikings because of their amazing eco bonus despite their bad tech tree.
Maybe it will boost their winrate. But it will be temperory. Remember celts could do this all this time and still opened archers → siege. Romans probably had the most viable militia-line in castle age with +2/+2. yet used cavalry.
Dravidian campaigns are a grind as it draws to the end. A campaign featuring the cholaa-chalukya wars would be good.
Aztecs get eagles which are exponentially better than light cav without armour for finishing the game by taking dowm defensive buildings. Woot steel does not work on buildings. they need siege engineers.
massing elephants in 1vs1 is only possible on closed maps. Dravidians don’t get any bonuses to do that. So Siege is their current best option.