Remove the Bonus Gold from Triumph
The heal on Triumph is good enough to stand on its own, particularly for a minor rune. As Riot has pointed out, Triumph overshadows all other runes on its row. The fact that, if every member of a team has Triumph and they all participate in a 5v5 and end up killing all 5 enemies, that this rune ends up giving out 500 additional gold to that team, is insane.
Presence of Mind and Overheal are both interesting runes in their own right and should be able to compete with the old Dangerous Game, but with the extra gold you see Triumph on tanks, on mages, and on other classes that should have no interest in the attack speed provided by the Precision tree. Triumph even detracts from other GOLD granting runes like Magical Footwear as a secondary because it gives comparable gold over the game as well as a heal (and an attack speed buff compared to what the Inspiration tree gives).
The rune is also basically a requirement on the Howling Abyss for obvious reasons.
It's been nerfed once, and that was a good change, but honestly the gold aspect of Triumph isn't interesting. We already get a gold reward for kills, it doesn't need to just inflate further. Perhaps if Triumph isn't strong enough as a minor rune with just the heal, you could make it give a short movement speed boost as well?