Ah, a serious theorycrafter. Actually I've been tinkering with some ideas of my own on topics like these, and this seems like a cue to post what I have so far on one of them: the support/autofill problems. Perhaps you might critique it. It's a bit rough since it's just from my notes file, but you'll probably get the idea. It starts with the UI grid that lets users specify how much they want to play which role (the abbreviations for positions represent the "default" position users customize from,) and then starts explaining how it all works in theory. Disclaimer: I'm a programmer, so this comes strongly from that perspective, and this is holistic, encompassing position selection, small but productive rewards to promote queue health, and theories on how queue health works or can work:
Grid 6 high, 3-5 wide (4 columns on row 1, 5 columns on row 6, 3 on rows 2-5)
1- - - - 1st pick, strongly prefered, system will first try to create balanced teams using this row only
2- - - 2nd pick, only used if adequately balanced teams couldn't be formed with everyone using roles from 1st pick
3- - -
4- - -
5Fi - - 5th pick, least desired, system tries these only if all previous rows failed to produce balanced teams
-To Jg Mi Su Ca Not willing to play or implied not to matter if Autofill isn't in this row, since Autofill enables all roles
Each position is an icon that opens a dropdown box when clicked, with the 6 possible icons; selecting one also removes that icon from its previous position on the grid
If one or more of the topmost rows is empty (as in the default) the system automatically treats the first occupied row as if it were the first row (e.g. the default is to fill with all explicit roles in the unused row to be moved up based on player preference, possibly putting fill in the place of the prefered role; if fill is left in row 5 as default, they will usually get their prefered role(s) but will fill if absolutely necessary to make a team, which is an excellent default for queue health)
Letting people clearly express their willingness to play roles should improve queue times due to greatly reducing dodges compared to just forcing people to autofill even if they're sure to dodge all autofilled games
Dodges increase queue times both by failing game creations and by taking dodgers out of the queue for potentially long periods, further reducing the material the matchmaker has to try to create balanced teams with; thus, involuntary autofill is inherently a bad thing and not useful as a solution; it must be voluntary to work
Number of matchmaking passes (how many rows had to be enabled to form balanced teams) will be a very useful figure for this system, both average and % of made games with each number of passes; separating made games by dodged vs. not dodged may also be useful data
Reward queueing with Support allowed (regardless of whether it's assigned) with a slightly higher IP scale; this will automatically reward Autofill in kind; the higher Support is on the list, the higher the scale reward should be, possibly only rewarding for Support in row 1
Because of Support's position relative to queue health it probably isn't necessary to reward having many positions allowed high in the position list, but a smaller, almost unnoticeable additional reward might improve queue health
Possibly reward playing when actually assigned Support with higher LP gains/lower LP loss, but only if no one reports you that game, possibly even only if someone not in your premade honors you (Supports in 5 man premades do not really need the benefit)
IP scale rewards should probably also be conditional on not being reported in that game and possibly further scaled by the number of non-premade players who honor you, such that being honored by all 9 other players while queueing solo gives the greatest bonus
IP scale bonuses (and possibly role-related LP adjustments) should probably not be shown in the endgame screen and possibly aggregated to a daily award to avoid people knowing too much about their being reported/honored; the number shown in the endgame screen and immediately awarded should be the base
Support IP bonuses could potentially be applied to even Normal Blind Pick with positive effects on queue health, even though Support is less clear there; Autofill obviously doesn't meaningfully apply
Why does Autofill still need to be an explicit option in this system? To make it easier to move it around, encourage selecting it, and remind everyone on a fairly frequent basis that Autofilling is encouraged, helps boost queue health, and cuts their personal queue times; it's psychological
While the system is first and foremost for Summoner's Rift Ranked and Normal Draft Pick, once it's proven in those roles I think partially expanding it to SR Blind Pick and maybe even SR bot games with appropriate modifications could improve the game. Especially for bot games, adding "Off-Meta" and/or "Roamer" options, perhaps more, while giving the matchmaker much more flexibility in assigning teams compared to Ranked, could help reduce dodges and make people happier; perhaps even just keeping the normal role selections and adding flags for whether you intend to play substantial off-meta and/or want to play with other people who are playing off-meta; the queue times on these queues are already very low with huge player bases (which affords much greater flexibility in adjusting who joins who without significantly increasing them,) but minimizing dodges and teaming compatible players are still useful goals to improve player quality-of-life
Adapting the system to Twisted Treeline should perhaps be eventually looked at as well; it's also possible some modified form of it could be applied to modes like ARAM in ways that boost queue health; all likely areas for expansion should be kept in mind where practical when implementing the system