Why doesn't Riot make reasonable changes when balancing champions?

In general referring to the changes to Phoenix Stance on PBE but I've noticed this a lot when I see balance changes. So previously before 6.4 Udyr was really strong in the jungle. I personally had no problem with him but a lot of people complained his Phoenix Stance was too strong and AP Udyr was a menace, etc. So Riot nerfed him.

After these nerfs a lot of people still struggled against Udyr and there was still complaints of him doing too much damage. So Riot nerfed Phoenix Stance again in 6.7, this time really hard. Phoenix Udyr fell off the face of the planet and led us to today. But instead of doing small buffs like the obvious middle option (30/70/110/150/190), Riot is buffing him to pre 6.4 values (In exchange for the DOT effect lasting a second less).

My concern here is if you felt the need to nerf him not once but twice why would you revert all the base damage nerfs instead of at first trying the option in the midde which probably would leave him where everyone wants him? And if that wasn't good enough, you could always buff him again next patch. But these changes almost certainly will be a restore to Udyr dominating and people screaming for nerfs once again.

It's a trend I see Riot's balance team engage in frequently and I just don't understand it personally. If you're trying to balance why don't you start with the balanced option that makes sense instead of constant over buffing and then over nerfing to compensate?