In light of Banner of Command, I feel like it is relevant to bring up just how noxious it is for items to define metas by going back in time a bit and showing the overarching effects that can have on so many other things than just itemization.
**1. It Limits Champion Viability**
So, let's go back a LONG time for the start of this one, and talk about a couple of the first metas that were defined by items; specifically Atma's Impaler and the original Athene's Unholy Grail. (For anyone that doesn't know, Atma's gave a HP to AD ratio of 2%, and original Athene's gave essentially infinite mana regen, 90 AP, and something like 60 MR.)
At the height of those items power, they utterly defined who was taken mid and top. Atma's virtually guaranteed that only champions that could make use of both AD ratios and auto-attacks could be taken top lane; but especially those champions that could abuse the original metagolem or champions that specifically countered that. Athene's was even worse because it ensured that only mid lane champions that could make full use of its suite of stats were viable (rendering almost all magic damage dealing mid lane assassins utterly inviable), and making ad assassins seem far more powerful than they were because they weren't almost entirely invalidated by the defensive stats given by Athene's.
The net effect of these items, ultimately, was that dozens of champions were nerfed before the items were nerfed; and many of those champions took months or years to receive compensation buffs when Athene's and Atma's were nerfed. Many of the champions that lost out due to direct nerfs and nerfs on those items, honestly, didn't recover until another equally potent item filled the void that they had left.
More recently the Ardent meta did the same thing, with lots of enchanter supports being directly nerfed before Ardent was weakened enough that it didn't define the game anymore.
Banner of Command is now doing the same thing. Top lane has seen a sudden influx of tanks that can make use of defensive stats without health (like Cho, Sion, and Maokai because they get some kind of built in bonus to their tankiness) because they can rush it without significant issue. Quite literally a week ago Cho and Maokai were viewed as VERY low tier picks for pro play, but now their are worth picking/banning in the first phases; as well as picking/banning their more direct counters. In spite of Eve, Rengar, and Kha'zix being more viable than they have been in ages; Sej and Zac are still two of the dominant picks because they can viably build Banner second or third.
In short, items should not be what dictate what team compositions are viable.
**2. It Forces Specific Builds**
This one is actually even worse than the first, and goes from the open beta up to the present day (and there is more than 1 item doing this, tbh.)
I could talk about how Zhonya's Ring worked (it was literally Deathcap AND Hourglass in one item), or how Atma's defined metagolem (and literally was a prescribed 3-4 items), or how Athene's made quite a few other items utterly invalid (think all other mana regen items on every champ but Anivia/Kassadin), or how Morello's did the same (until 8.4, but Archangel's seems to be carrying that torch now), or any of the various Blue Ezreal builds, or any of about half a dozen different jungle items that dictated that only carries or tanks could be picked, but most of those aren't the worst offender on this one.
The worst three for this one were original 'support' items, Banner, and Bloodthirster.
The original support items gave increased gold per 10. The thing is, at the time, supports absolutely had to build at least 2 of them and that dictated what items they could actually even hope to finish most games unless they were involved in a _lot_ of kills. The thing is, lots of other champions would, could, and did build the same items, but often held on to the gold generation items and swerved what item they would finish first to maximize their early income; as well as gaining generally beneficial stats. (The worst were HoG and Philo Stone.)
Next was Bloodthirster. Essentially, once upon a time, ADCs rushed this item because it gave the most AD when stacked (100) as well as 25% lifesteal. While this didn't change the pool of ADCs that was picked; it DID dictate the builds on opposing champions and forced ADCs into almost their own metagolem after building it because while it was the best AD and sustain available, it created a black void of damage for ADCs until they finished 3 other items because they still needed attack speed, crit, and armor penetration. So, it almost always went something like BT-PD-IE-LW with boots thrown in for spice.
Even worse, it also tended to force ADCs into squishy rune and mastery builds so they could have any kind of damage spike at one item because they had to include as much attack speed, crit, and armor pen in their pages as possible.
Banner is, perhaps, the worst part of both of those at the moment. By all appearances it is a support item that can be used situationally top lane given its price and generally suboptimal stats. (Toplane tanks tend to value HP more highly than armor/MR on their own.) Except now Banner is dictating builds in top, jungle, and support because of the power of 'Banon' minions, both in build order and other items that are chosen.
EVEN WORSE, the only solvent counter to Banner is changing a rune build at a time when each player gets all of 6 runes total, AND how they use that rune is essentially dictated because if you use all of the charges of minion dematerializer you open the door for someone on the opposing team to build Banner because its only functional counter is gone.
**3. It Makes Games Hopelessly Stale**
I'll admit, this one is subjective, but I think that most people would agree with me when I say that seeing up to 6 total champions in a game build an item with the hope of abusing it the same way is woefully boring. This is made even more boring when you add in that item metas dictate which champions are most viable thus narrowing the pool of 'best' champions, thus narrowing the pool of champions that are most often played. This is made even worse when specific runes must be picked to viably use or counter the item in question because (especially now) it narrows what rune pages are even used.
While this isn't as bad for the average player, but it is super obvious if you watch pro games. I would be, quite honestly, floored if I found out that even 40 champions were picked and banned this week in NA and EU.
Now, this problem isn't only caused by Banner of Command at the moment. IE+Double Zeal items is almost as bad, and it looks like Archangel's could join that group as well. I could make another entire post about those items and why they need changed (and a lot of it would overlap with this one), but those are discussions for another time.
**4.They Take Longer To Fix**
So, if I went back over every most significant meta defined by an item, the average lifespan of that meta would be, at a guess, between 8 months and 1 year. Some of them lasted for entire seasons, like Atma's, BT, OG Athene's. Even a relatively short meta defined by one item tends to last at least 2 patch cycles; which would be about two week's at Riot's fastest (years ago) and closer to a month now.
Champions tend to get hotfixed or nerfed into the ground relatively quickly; usually no more than a couple of months.
Which is how something like Metagolem was THE THING season 2. Or BT-PD-IE-LW was THE THING for like... 3 seasons? Or how Ardent was THE THING for the back half of last season and all of worlds.
In short, item metas are THE WORST. If you want more info, there's a lot above.
I hope, against all past evidence, that Banner will be nerfed soon.
I don't think it will be, and I think anyone who watches pro play is in for some VERY stale champion selects **AND** matches decided by either Banner or Minion Dematerializer. I think people in Solo-Q will be split between favoring those same champions (without the Banner), trying to use Banner unsuccessfully, and people actually managing to make use of Banner with at least some success.
Honestly, as a person who only recently came back to playing the game again after a nearly 2 year hiatus because I was done with a stale meta this really wasn't what I was hoping for at all.