Unlocking more Mastery pages

(If this can go in another forum, please tell me, though I don't think so)

TL;DR -- Let us buy 5 extra Mastery pages for the price of 1 extra Rune page (590 RP || 6300 IP), or via Champion Mastery, up to 20 extra pages (40 max total).

_Some people are able to edit a mastery page within the time it takes for a match to begin. But what about people who play Blind, or people who want to select a page and be done? Sure, some players only use a select amount of champs, or champs that utilize the same kits, but personally, I like to play whichever champ I feel will give the most to my team's composition.

I have all 20 pages filled up, with 4 of them dedicated to certain champs and 3 for ARAM specifically. If I wanted to play Dominion or TT, I'd have to temporarily replace one of my pages, which I'd likely forget to do anyway, possibly leaving me with a useless mastery (i.e. Butcher on Howling Abyss or Crystal Scar).

Yes, the mastery selection drop-down menu is somewhat clunky and buggy (sometimes I have to click a page twice for it to select, and sometimes the scroll bar closes the menu), so having more things there could make it even worse to navigate, but it'd be nice to have the option to access more Mastery Pages, so many that I could have one for each specific role/matchup that I'm likely to play._

Basically, my idea is to allow the player to purchase/earn additional Mastery pages, either through RP/IP (a la Rune pages) or perhaps somehow through Champion Mastery, or maybe even have some pages included with each Rune page purchase. Ideally, the maximum number of Mastery pages would be 40 (20 we have for free + 20 earnable/purchasable).

Sorry if this seems like more of a rant than a suggestion.