Title. I am never going to invite premades, especially 3-4 man stacks to me 7-10 keys because of the obvious tribe mentality and them ganging up on people in pugs.
Give us the option to automatically decline/filter them out of the list of possible joiners becaause all they do is clutter the list. Another great one would be an option to filter certain servers like all the Russian ones.
E: I forgot to mention all the boosting in premades so there is always bound to be bad players there.
This is the biggest “non issue” I have seen in a while.
You dont want to invite premades, then dont. Press the X.
I prefer not to invite RShamans in my keys. Because I am a RShaman. So I press the X when one shows up.
As for filtering russians, you can already do that.
Use the Premade Group Finder [PGF] addon, believe you can filter for new groups forming.
Rshaman is 1 person its the issue of the window being so small and being spammed by trashy premades.
How can I filter Russians though?
It is not being spammed by trashy premades.
And you are over exagerating. You had a bad experience with ONE premade. And you put them all in the same bucket.
I play with 1 friend all the time. In a “premade” of 2. And I have such a great sinnergy with my friend (because I have played with him daily for YEARS) that its a net benefit to the party. And we both carry many groups with mechanics.
Its in their name. Cyrilic is not enough? 
The real question is how can I filter UK?
Had some very good russian players in my keys.
As for pre-mades, yeah, maybe its best to avoid them, especially if you’re a tank joining one.
ye i would like to fillter people from Kazzak,Silvermoon also i want to fillter russians and spain and portugese…
And so on and on
Dont filter spanish servers !
I play in one. We will never meet if you do ! 
That makes me a sad RShaman…
We only join m+ as a group of 2 as we like to run them together never had a problem getting in groups.
But it’s a non issue just ignore them
I’ve had 0 good experiences with german premades 
Still a non issue for OP tho idk
I mean a lot of countries outside of Russia uses cyrillic…
It’s a well known issue and saying “my anecdote is more valid than yours” is just goofy especially when you are probably under 3k RIO last season.
It dosent matter. You can only discriminate by region, not by nationality.
You would need to have access to the personal details of a player to discriminate by nationality. All you can do is say: Russian region NO.
And ALL servers in the russian region have a name in Cyrilic.
Then why post on a English speaking forum if you dislike the UK you dont have to come here.
Thats why you are posting on a classic char and hiding just like me then i guess
No its not a well known issue, its a ‘you’ prejudice.
The counter point is a premade will have better co-ordination and poss be on comms which makes them more valuable than 4 randos.
Also, rich of you to score shame on anlevel 37 troll alt.
Why would you filter Russian players, they are better than most EU players.
I would rather filter Germany, France and Sweden - but they do not have their own servers and therefore I cannot see if they are from any of these countries. Just make guess work in terms if the player is from Kazzak, Archimone etc…
Score shaming on a L37 classic alt, that´s rich…
Germany and France do very much have their own realms, literally dozens of them.
The counter point does not matter because in that case they can run their own key or go full 5-man. Instead what is going to happen is that due to their tribal mentality they will treat the random keyholder as a NPC and if something goes wrong, especially if they are a tank or a healer, the premades will gang up on them and have an easier time leaving they key because they are justified by their friends.
You are posting on an alt yourself but atleast you have the balls to show that your rio sucked on a meta spec and with premades too which makes your first point even more moot.