to have a system of allowance in solo/duo (ranked) champ select?

How it would work:
-If a player is trying to select a character that seems to overlaps in role and position with another already selected, his team has an opportunity to veto his selection with 3 votes against. (examples: someone trying to select Ashe with a Caitlyn already on his team; someone trying to select Brand with a Heimerdinger already on his team; someone trying to select Nasus with a Yorick already on his team.)
-There is nothing to keep the team from accepting a sensible, agreed-upon champ selection, so the system shouldn't cause any issues in that way.
- If the player's selections are all vetoed, he will be assigned a random champion that would not require allowance (i.e. a versatile champion or one belonging to a role that hasn't been filled)... or that player could be booted with the normal penalty for dodging.
- If a player can make a case to his team, by reasonably communicating his intentions and ideas, there is a good chance his selection will not be vetoed. He can even say things like "Look at my Ashe win rate on LoLking; that was done mostly in 'support' role."

Basically, I feel like the most common type of trolling is a late-pick player "calling" a position, and then refusing to play another position, regardless of what is picked. Yes, I know that the conventional meta is only a guideline, and not a law. Yes, I know that Ashe and Caitlyn can be a successful lane combo, especially when unexpected. But is there something so wrong with a team having to agree to the implementation of an unconventional strategy? Generally those strategies will fail if the team is not on board anyway.
I get that players would complain that their "freedom" was being limited, but it would really only be their "freedom" to go against conventional wisdom, demonstrated effectiveness, and their own team's wishes. If you want to try an unconventional strategy, I believe it should be done with an arranged team, or at least in normal.

I dunno some champs can handle multiple roles. Like Vi can Jungle, top, solotop, bot, bot support and even perform average in mid.

Kinda unfair how people are completely bound by the meta and therefore bound to play specific champs.

Dunno how long it's been since I've had the privilage of playing Nassus or duo bottom instead of support+adc.

What happens when you veto the player's first two picks because you don't think they combo well with the rest of the team, but they happen to be the player's only good two champs. You've just caused the player to have to play a game with an unfamiliar champ when the team is *already* hating on them for picking the "wrong" champ. Unfamiliar champ + raging teammates ≠ win. It's better to have them play a champ they know & can do reasonably well with, even if it doesn't fit the majority idea of good team composition.

SomeCallMeEd- I said if they are trying to pick a champ that seemingly overlaps with an already selected champ's role. Any versatile champ, like Vi, Nunu, Galio, etc. would never be eligible for veto.

Senor Blanco- A team could not veto a selection just because of "poor fit." A selection would only be eligible for veto if it overlapped a role. For instance, if two solo-lane dependent champs (Veigar and Nasus for example) have been selected, a Brand selection would be eligible for veto.

I've seen support Brand played. How would that be dealt with, if 3 of the other players on the team didn't like the pick?

And you say they'd be assigned a random champion - Oh ****, well he just randomed Kassadin. Looks like he's well and truly ****ed.

Riot won't assign "roles" to champions. Remember Zyra? She was supposed to be an AP mid, but she's a support now. They make champions, Phreak says what he believes in the champion spotlight, and then people (generally pros) find the best way to play her. Riot isn't going to assign the roles to a champion because that would do two things - one, disallow innovation because they're forcing certain champions to certain roles. And two, disallow innovation because they're forcing the meta.

And the dodge timer? What if I want to play Singed support, and my team wants me to play Sona? My team is just going to say no and boot me from the game, causing me to lose 5/15 minutes of my time.

So the voting would only affect the last 2 or maybe 3 people picking?

This could screw a lot of people over. I could call AP mid, then I'm with a group of four people who are a pre-made team which had someone who wanted to play AP mid, they could just veto my pick, even if I'm first pick. The idea is intriguing, but it just doesn't seem like it would work.

AD Bottom- Brand could be played as support, if 3 out of 4 of your teammates are okay with that.
You would only be assigned a random champion that didn't overlap in role, and that you owned* (adding this now.)
Good point about role assignments being limiting. No champion would be eligible for veto that hasn't been out for at least 1 month. And as I said, a champion that wasn't clearly meant for one role, or who didn't strictly depend on a solo lane, would be eligible for veto. A Zyra pick would [almost always] be safe since she can play support or in a solo lane.
Singed may be categorized as support, as well as solo, thereby making him immune to being vetoed if support hasn't been picked. If he is not categorized as support- which in most people's opinion he should not be- then he would likely be eligible for veto, but only if two solo-lane-only champs had already been selected. And you only get booted after multiple vetoed selections. If you get vetoed once, stop trying to be unconventional.

OlGrizz- the vetoing would tend to affect later picks, who of course should have decreased priority in selection compared with those who are higher ranked. That being said, 2nd pick could be affected if he tries to select Corki when Vayne has been selected by first pick.. or if he tries to select Taric when Sona has been selected by first pick.

Saikuetsuei- No. A) First pick would never be eligible for veto, based on what I described. B) You will never be with a four-person premade team in Ranked Solo/Duo, which is what I am talking about.