It would give the variant much less 'Shogi feel' when you introduce such an exotic move. I am also not sure whether in Shogi Soaring-Eagle-like Lion capture would do really much more than a two-square jump (or even slide). The locust capture is mainly dangerous because it can eliminate protected pieces. But in Shogi the main factor that determines the value of a piece is how effective it is in checking a King. And there you don't care whether it was protected or not. Starting to hunt for other material by dropping, promoting, capturing takes too long, and you would probably be checkmated before you get the opportunity to drop the piece you gained by it.
Although I think that in Shogi the promotion Silver to Gold was mainly motivated by uniformity, it is not an entirely useless promotion. When dropping a Silver in front of the King to check the latter, the King can evade by stepping next to the Silver. The latter can then pull backwards to renew the check, and by promoting to Gold in the process it can make sure the King now has to retreat.
It would give the variant much less 'Shogi feel' when you introduce such an exotic move. I am also not sure whether in Shogi Soaring-Eagle-like Lion capture would do really much more than a two-square jump (or even slide). The locust capture is mainly dangerous because it can eliminate protected pieces. But in Shogi the main factor that determines the value of a piece is how effective it is in checking a King. And there you don't care whether it was protected or not. Starting to hunt for other material by dropping, promoting, capturing takes too long, and you would probably be checkmated before you get the opportunity to drop the piece you gained by it.
Although I think that in Shogi the promotion Silver to Gold was mainly motivated by uniformity, it is not an entirely useless promotion. When dropping a Silver in front of the King to check the latter, the King can evade by stepping next to the Silver. The latter can then pull backwards to renew the check, and by promoting to Gold in the process it can make sure the King now has to retreat.