People that bought runes and are complaining about being ripped off
Are forgetting that they actually got to use runes that entire time. You already got a ton of value out of them. And it's not like you're going to be at a gameplay disadvantage to people who didn't I vest in runes.
Would I like a higher amount of IP refunded? Of course. Do I want Riot to bankrupt themselves trying to give a "fair" amount of IP back? What do you think?
Look, they don't wanna give a gameplay advantage to people who got runes in the past, they've made it clear that they don't like giving big fancy "Exclusive" content (because a big sell for league is that everything you see, you can get for yourself. Everyone's on the same level, to start), and the exclusive content they are willing to offer, loading screen flair and icons, has been very poorly received.
Their only option is to give us things available to the general community, and if they actually gave a satisfying ratio of IP back and made the costs of items in the temporary IP store reasonable, then some of their most dedicated consistent customers would end up with a ton of basically free basically rp, buy everything they want, and never spend a dime on the game again. Obviously that would be fun for us, but it's not hard to see why they're doing it this way.
I'm not thrilled by what I'm getting either, but in this case, Riot's logic is internally consistent. It's completely predictable, and people that are shocked have no right to call themselves veterans - I don't care how long you've played leage, if you didn't see this coming you might as well have started yesterday.