I would replace it with elephant units move 40% faster and replace Persians Imp unit tech with something else (and make +30% speed included as part of elite war elephant upgrade).
Few civs desparately needs a compensated mobility boost than Dravidians.
Specific consequences of this speed boost:
Battle elephant: 0.85 > 1.19 (8% faster than fully upgraded spearman line 1.1)
Elephant archer: 0.9 > 1.26 (between fully upgraded eagle scout 1.21 and closer to eagle warrior 1.265)
This puts their speed on the faster side of the infantries. Would be nice to keep up with the infantry army.
Siege elephant: 0.6 > 0.84 (close to battle elephant without husbandry 0.85; for reference ungarrisoned Mongol siege ram with drill is 0.9).
If the devs would like to encourage the use of elephants, consider making elephants more viable for civs that get them. As the way it is now, HP regeneration is mostly pointless if you can’t run away from bad fights.
I hope the tone down urumi swordsmen a bit and add an extra dimension to the civ. This still keeps their supposed “bad cavalry” identity at the same time making the stables a bit more tempting some times.