Paying 590 RP for that one Chroma I want is not a good deal; the other two Chromas will be nothing more than junk clogging up my skin selection screen.
I could pay 390 RP for Assassin Master Yi and get new colors and a different model.
I could buy a 520 skin with new colors and a different model (Aristocrat Vayne, Atlantean Fizz, Bandito Fiddlesticks, etc.).
I do not want to pay 590 RP for one recolor and no new features + some unnecessary extra Chromas.
Before anyone mentions the possibility of purchasing one Chroma for 390 RP, like Riot originally proposed in their surveys, I don't believe they're worth that much individually.
If Riot wants to sell Chromas in packs, they need to be selected individually by the purchaser (ex: one Chroma for Classic Blitzcrank, one for Spirit Guard Udyr, and one for Guardian of the Sands Kha'Zix). Selling them in packs of three is not a boon to the customer when you remember that the customer is highly unlikely to ever use the other two. If a house painter offered to paint your house twice for a discount or once for normal price, you're going to end up with one paint job whether you take the "bundled" deal or not. Sure, you can switch out the Chromas (or skins) in League, but you're only getting one combination in each game, and you're quite likely to prefer one over the other.
I do hope Riot provides some Chromas for free through Champion Mastery, but I have a feeling that they aren't going to let players choose which Chroma they get, meaning players will want the Chromas Riot will be selling, not giving away...
It would be nice if Riot made these Chromas cheap in terms of RP, but they could also be available for a fairly large amount of IP (ex: 250 RP or 3000 IP).