how is kayle balanced?

Right now? Her numbers are being kept purposefully lower than ideal to keep her under control, because her kit is that bad.

She's in line for a full VGSU rework, and it has been said that she will be having a joint rework with her sister Morganna.

Because they keep her numbers pretty much gutted in return for having an inherently cancerous kit?

Gated by mana costs early, CDs and being squishy later on (her ult is much like Zils, if she uses it on herself, kite her out for its brief duration, if on someone else, she's now vulnerable). Also 525 range w/ E, 125 without (most marksmen are 550 or more, many mages have 700+ range spells). She at least has meaningful weaknesses, even if a strong late game.

very little range very little mobility not much burst bad lane matchups unless she counterpicks into top lane when top lane it probably means the team lacks a tank

Low numbers, gated by mana and CD early on, has to build 2 expensive items to even be meaningful in teamfights and in general(Nashor's and Guinsoo's costing a grand total of 6600 gold. Total early build at 7700 counting boots).

Not a lot of people who play her. Even less who actually enjoy playing her.

She's not. That's why she's getting reworked.

If you can't bully her out in the first 10 minutes, you likely lose. You just hard win if you do end up bullying her.

1 cc to her and bye bye kayle

Uh, don't let her get to late?