Feedback on Proposed Competitive Changes & Additions
I like that you're adding two new tiers to help diffuse the massive amount of players in Bronze and Silver without just artificially shuttling them into Gold and addressing the skill disparity in higher elo play as well. Wonderful. Don't get used to the brevity.
I hate the idea about separate MMR for each role, let alone the separate rank entirely. Even if autofilled, there should not be a separate MMR system. It is too easy for players to abuse this. I'm like a plat level support, mid gold jungler, low gold top/mid/ADC. I know this already. I don't need to be told that by the ranked ladder. I don't want to feel pressured into playing 30 games each in roles I don't like because I'd risk missing out on something if this becomes reality. Dota's solution to a player not getting their main is simple - get good. And that's exactly what this ranked system should encourage you to do. An example of this happening in real time is Cowsep, currently attempting to get Master tier on Vietnam. Master Yi is being banned a lot because of his presence on the server, and Jax (his backup) is being picked away from him and banned often as well. Is he giving up? No. He's started learning a new champion to play if those are off the table, and he's getting markedly better at it every time he has to play it. He's improving, doing exactly what the ranked system is supposed to make us do.
The idea of separating the season into multiple splits (without having to redo placements) is solid. It makes non-professional competitive play more similar to the eSports layout. A lot of players are going to enjoy that. While I don't particularly care about that aspect of it, I recognize that others will. Having some short defined breaks throughout sounds nice, though.
Clash is a good concept, but you have to do a better job of calculating MMR and moving teams up if they have a higher elo player on them - or not moving them up if they don't. A lot of low rank teams had awful times because they were against teams that had 1 or 2 players far higher than them take control of the game. A lot also seemed to be put into games that were a full tier above them for no apparent reason. Also on the topic of Clash, I don't recall clarification on whether 3's ranks had an effect on Clash MMR. Finally, the system needs to do a better job of weighting Flex MMR vs Solo/Duo MMR. Plats vs Challengers happened once upon a time in Solo Queue, and it seriously impacted the competitive integrity of the queue. If people who have played a fair amount of Solo Queue and are only Plat there are Diamond or Master in Flex, they probably ought not be placed against LCS teams until they've had some success in Clash (and thus, increased their MMR). Considering you have to be at least D2 Solo to even be on a pro roster, that seems fair.
The Victorious skins have been a hallmark since the beginning of ranked. It should continue, despite some players not caring about getting a skin for a champ they may not play. If this was a problem, the hextech crafting should be removed on the same principle, because people get skins they don't care about from that far more often than the once a year prize for competitive achievement. Icons, emotes, and wards do not come close to the value of skins (by your pricing models, and presumably by the opinions of most players) and should not replace the Victorious skin.
Mixed on the borders updating as you climb. I think updating after each split would be better. I personally like the idea that the border is more of a standing testament to your accomplishments (similar to the Victorious skins/wards), not a daily tracker. That's what your profile, the ranked tab within, and stat tracking websites are for.
The changes to placements regarding clarity are a godsend. However, I'm mixed on the process beyond that. I'd have to see whether or not it places more people higher than they belong than the current system, which as we know pretty much just drops every new account into mid silver unless you go 10-0 or 0-10. Also, you should be able to be placed higher than your last rank if your MMR means you deserve it. For example, I finished last season Gold 1 on LAN in solo queue, and climbed to Plat 3 in preseason. This season, I was placed in Plat 2 there, and I've climbed to Diamond promos since then. It would have been nothing less than a slap in the face for me to have placed no higher than my previous rank, Gold 1. When I was obviously good enough to be higher than that.
Hope you find this helpful, Riot. Aloha.