Victory Dragon as a Duel Winner instead of a Match Winner

[Zowayix]

Victory Dragon [DARK]
[Dragon/Effect]
This card cannot be Special Summoned. To Tribute Summon this card, you must Tribute 3 Dragon-Type monsters. If this card inflicts Battle Damage to your opponent [b]when it is the only card on the field, your opponent's Life Points become 0.[/b]
ATK/2400 DEF/3000

Getting out multi-Tribute Normal Summons in the current metagame, especially those of a specific Type, seems to be very difficult; however, it does have an instant win effect (which I based off a direct attack, like the original Match Winner card). I'm not sure how easy/hard it is to get that effect working, since your opponent must have a completely clear field and you can't have any kind of protection, not even from other monster effects.

How is it? Still broken? More balanced? Unplayably bad?

If it's too bad, or still broken, how can I adjust it?

[Zeppeli Gyro Supreme]

It's now an FTK card, though the FTK would be pretty convoluted.

[Suibon]

[center]It is still bad, but I'm afraid it is of the same cut as the Victory Dragon that you attempted to retrain. Luck out into removal and a few easily summoned Dragons or whatever they're running in Chaos Dragons or Heiratics, and you just won a Duel, regardless of whether your opponent has 8000 or 2400 LP.[/center]