Expand ARAM Roster

Seeing it more and more with each time I play ARAM. The same group of champs are still popping up even with the last 3 free champ rotations being included in the "random" selection. Or to be more specific, whichever last 3 rotation groups are being chosen from, its always the same champs from those that keep coming up.

I've brought this up before and I still stick by it:

Just make it so all champs are available in ARAM.

By doing so, it makes ARAM only accounts null and it gives players a true random selection. This way it also doesn't favor free rotation champs when rerolling. This way everyone has an even chance of getting any of the champs in the entire roster, and not just what's free and what matches up among all the personal rosters.

I know this would be tossing aside people with ARAM only accounts, but purposely not getting champs just so you have a smaller roster to get random from is just silly and cheesing the system. Besides, aren't ARAM only accounts looked down upon anyway? And since I've switched to only playing ARAM, wouldn't my account be considered "ARAM only" even though I own a majority of the champs?

In the past, someone did say that by opening the whole roster discourages people from purchasing the champs. Well for one, I highly doubt Riot makes most of their money from champ purchases, since you can get them with BE. But also, wouldn't opening the roster instead encourage people to buy the champs? What if the player really enjoys playing a certain champ and wants to get a skin for them? Then they'd have to buy the champ so they can get the skin they want.

Also, I can't be the only one that uses ARAM to practice champs that I don't normally play. Plenty of times you'll reroll a champ and the bench would be limited and none of the champs you like are available. At least for me, I'd just buck up and pick the champ I have the most basic knowledge of and try them out. This way players can test out the basics of a champ in a teamfight setting, but without it really mattering.

Overall, I just think there's more pros than cons to opening the whole roster for ARAM. But please, if anyone can think of a downside let me know because this seems like the least biased system to be set up for ARAM.