Rune price and autofill
Runes cause serious issues with autofill. People often respond to threads about rune cost by explaining you don't need them all, and only really need 10-15k IP worth of them. However with autofill there is a chance at getting any of the 5 roles. The tired old excuse of you only needing one rune page doesn't match how autofill works. If I build one good AD rune page I might wind up stuck in support getting almost no benefit from it. If riot wants me to play every role, I need to be able to get runes for every role. If this doesn't happen my entire team gets to suffer from an inferior support who doesn't have runes. (or inferior ADC, Jungle, Top, or Mid)
I for one am perfectly fine with the idea people need to be able to play any role. I am fine with learning every role. Grinding runes for every role is another thing.
If I wanted to get runes for Jhin, Yasou, Annie, Vi, and Blitz, then I would have to grind a massive amount of IP. This is just for one of each role, the runes you would need:
**9x Greater seal of scaling health - 3690 IP **(These are fairly multi purpose, I'd probably prefer armor for this slot on blitz, but these can be reasonably used.)
9x Greater mark of critical damage - 7380 IP - 11,070 Total IP (These seem like a must for Yasou, they increase his damage by roughly 10%)
9x Greater mark of lethality - 3690 IP - 14,760 IP Total (Consider this is dual purpose marks for both Jhin and Vi, I'm not trying to make this look like the maximum IP to play 5.)
9x Greater mark of magic penetration - 1845 - 16,605 IP Total (These are a little more reasonable, and can double for both Annie an Blitz, since Blitz doesn't have good options for marks)
9x Greater glyph of scaling ability power - 3690 IP - 20,295 IP Total (Glyphs for Annie)
9x Greater glyph of scaling magic resist - 1845 IP - 22,140 IP Total (Fairly decent on anyone, I'll count these for everyone but Annie's Glyphs)
3x Greater Quint of Lethality - 3075 IP - 25,215 IP Total (Jhin and Vi)
3x Greater Quint of magic penetration - 3075 IP - 28,290 IP Total (Personally I'd throw on spell vamps for the sustain, but these are probably the usual pick for Annie)
3x Greater Quint of critical damage - 3075 IP - 31, 365 IP Total (Yas)
3x Greater Quint of armor - 3075 IP - 34,440 IP Total (Eh, Blitz didn't have armor because I used the health seals for all)
That is 34,440 IP for some moderately prices rune pages with a fair amount of reused runes. If you wanted to buy rune pages with IP and not RP that would be another 12,600. (considering you only need 4 since the Jhin and Vi runes are the same.)
I've been almost every day for months and my lifetime IP gain is 57,000. You're looking at about 3 months of IP from a regular player for those runes. That's assuming they buy all their champs and the rune pages with RP. This is some crazy ass time gating, and not even the worst of it. If you want to play a mixed damage character, those mixed penetration runes cost double the regular ones for some reason. If you wanted energy runes for those ninjas? Just don't play ninjas. Maybe you don't want to use scaling runes, but instead all early game power to help get an early lead. That would be especially good on Kindred, as it would help them stack if they were stronger earlier. Well if you want to build anything unusual, be ready to cough up thousands more IP.