First of all, I agree a lot on the item icon part of yours. Below you have the opportunity to read, why it is currently difficult to achieve for Riot. They are much more organized and logical today – even though it doesn't seem the slightest for a lot of players, that are just not that much into trying to looking behind the curtain.
It still is important in the long run though, that we get full high quality item icons as standard like the updated Deathfire Grasp (RIP), which IronStylus who sadly isn't a part of Riot anymore, and some others actually put a lot of thought into.

Not even counting all the new icons and some I've definitly missed, all these icons got beautifully updated and that even faction related.
With these in mind the potential for the items below is just insane and gets me hyped!
Shadow Isles
Targon (Leona, last two maybe Kayle related if she'll be Targonian)
Urtistan (Zilean related)
Void ( the staff Kassadin, Malzahar or simply Void design related)
Ionia (originates from ''Masamune'', hit google – Ionian is the clear way to go)
Demacia (…like Randuin's Omen – Garen or Jarvan IV related)
Targon (… fits the full name the best, – Ionia, Freljord or Shurima still could fit though)
Demacia, Ionia or Void (many possibilities – for example Fiora, Akali or Kha'Zix related)
I think a lot most players would agree on the importance, that League needs finally overall visual consistency in the game after all those years, with items being a huge mostly untouched part of it. Too much at once would create uproar though, because a lot of players who don't play League that much (and are too lazy to at least scroll over the patch notes – sigh) would get irritated, having problems to find them in the shop. In my personal opinion single changes, small and sometimes a bit bigger batches would fit nicely for this, getting people more used to it.
Especially the League community can be, in a friendly tone that isn't actually my view,
VERY questionable when it comes to change.
By the way, there are even more like
,
&
, which aren't even on your list, because they already got their icons updated – even having different states of -high- priority.
I think Riot just realized, that a lot of cases are just a huge waste of resources and just delay bigger updates. All the straight VGUs that happend made sure, that these Champions don't need any further cosmetic update in the future and so are completely of the list unlike
for example. His model is even inaccurate to his splash art. His model has green crystals on his armor, even very noticable on his forehead, his splash has it completely missing and his eyes are significantly different though.
It is just all a matter of resources, priorities and effectivity for Riot.
Having to do with that they still get huge backlash for
not having new VO and individual other stuff, which I often still find overdramatized by the community; it is pretty clear, especially by a newer statement by Jaredan (in in his case in terms of VO/lore), that Riot will definitly come back to their individual needs, it just will take a long time, because they already got some pretty significant love and it is a matter of opportunity and the other factors stated above.
Good thing is though, that in the next 2 to 3 years we will get probably rid of all the ''worst offenders'', which are an overal mess.
are already of the list.
already on the way.
already on the (very) high priority list.
All these had/have huge problems with their theme, gameplay, visuals at the same time.
There are also many others and even more Champions, like mentioned by GreenLore, which are also considered to get a VGU in the future.
Things will get interesting, when the most horrible are all finished, because Riot mentioned they will also do smaller VGUs, when kits are already pretty nice, unique and functional, but need a little polish/modernization or just more strategic uniqueness.
I am really asking myself how the time between ChampUp releases will be then, praying it will be a much smaller time window, reminding of the times when
got VUs, just a bit longer, because of gameplay kit touchups, though with more focus on visuals and a much straighter stance on theme in mind. Their infrastructure is much better and professional today, so I am really excited and looking forward to having faster surprises for us in the bit further future.
PS:
Icons are totally fine and
icons got overall polished with the Assassin Update, not just his Q, made them much more high definition in general. It just wasn't highlighted/noted on surrenderat20 for example or by Riot itself.