The league of human is shit, but I was experimenting around in casual and found this extremely viable for Xeniel especially when you have coordinated teammates.

Basically you want to go in first into a team fight and soak as much damage as possible, you'll probably die but that's okay since you can just revive and fly back immediately and effectively turn the fight into a 6v5. This usually catches the enemies off guard, and can turn around crucial fights during mid/late game. You can also be a really aggressive split pusher with this setup since you can just revive and ult back if you die.

Downside is that your teammates might be surprised as well and disengage once they see that you decided to stupidly "suicide" and your efforts are wasted. You might also end up being hesitant to use your ult during fights for when your ADC/Jungler gets targeted, and end up being useless, which is why this works better with coordinated teams.

If used right, you basically have 3 6v5 chances during the match and it could turn out pretty OP.

Had this one game where the enemy was doing slayer and I went in to contest with my team following (thank god). I took a bunch of skills to the face while my team engaged as I revived and flew back. Ended up killing 3 of them as we stole slayer, and won the game from there.