The more champions that get added, the more variables you have to take into account when you balance. Rather than trying to spice things up with a new champ, how about the challenge of making Tryndamere and Jax fun to play against. Or how about making melee vs ranged matchups in lane not feel like endless suffering. How about revamping Nasus and Veigar to be not infinitely scaling? etc etc
The game will never have true balance. It will constantly be changing regardless of if new things are added or not. A good example is Super Smash Brothers Melee. It took the community a very long time to realize Jigglypuff was a good pick, and the game hadn't received any changes. The game is fairly balanced as is. It's not perfect, there are always things that can be improved, but that doesn't mean you can't add new stuff. It keeps the game interesting and fresh.
It is not possible to perfectly balance and game where the player can make choices (Runes/Masteries/items) and if they tried the game would become boring because it would de-evolve into playing a single set of champions that are objectively better than the others at what they do.
Imbalance is what allows diversity.
Because if we waited for there to be perfect balance, nothing would ever get done. And truth be told, the game is better balanced now than it ever has been. If you don't believe that's the case, then let me remind you of the reasons why dodge was removed, or AD scaling, or Old Poppy and Sion, or before Unique Passives were a thing.
Fun fact LoL is arguably the most balanced of all MOBAs. Dota players have told some pretty horrid stories.
Gee its been a while since I have ever seen a nasus infinite scale complaint thread when the boards almost unanimously agree that nasus late game is, ironically, useless compared to his mid game
Players just need to accept that there are champions like 
and 
who can infinitely scale and are (thematically designed) an absolute nightmare by the mid-late game.
Its normal that there are champions who are more early game focused 
, or late game focused 
. Champions who are more focused around teamplay 
and champions who are all about themselves 
.
There will never be equality in League of Legends, because every champion is unique and has its strengths and weaknesses. Veigar has an incredibly strong mid-late game, but is really vulnerable in the early lane phase.
Nasus and Veigar are themed around infinitely scaling, it's not a balance error. It makes them unique and its who they are, what you ask is like taking away 
's turrets.
Now Im not saying Im 100% satisfied with League's current meta, but you just have to accept that there are some champions that are extremely powerful in the right hands, just like 
, and if you want to be able to beat them it'd be a wiser decision to start understanding what theyre capable of, while leaving aside your personal opinion over them because Riot will never ever be able to "completely balance" LoL by the taste of every single player.
You know, you had my attention, and I was opening this thread with an open mind. You kinda killed that. Pretty quickly.
Before continuing, allow me to say I agree with the title. I have stated in the past that I would rather Riot first make a selection of skins they can drip-feed over a season, and then stop new champion and skin production. With this newly released manpower, it allows for Riot to focus their efforts on bringing the game up to speed with all the new variables that have been added since LoL started, as well as provide older champions with much needed VUs which would produce more income for older skins as well.
I would call this the Season of Maintenance.
Now, let's get to your post.
how about the challenge of making Tryndamere and Jax fun to play against
Jax is actually quite fine to play against. Tyrndamere, admittedly frustrating, but he's not impossible to deal with.
Or how about making melee vs ranged matchups in lane not feel like endless suffering.
Then why bother having Melee and Ranged champs at all? Ranged champions have a distinct advantage over Melees in terms of range (at least before Riot started adding built in flashes with pretty much every new kit), but when these Melee champs manage to close the gap, what do you think happens? They punch the Ranged Character's face until their health goes away.
Nya haa, I counter you.
-Smirks- Demacia.
-Five levels later-
Dead Teemo. Moving on.
How about revamping Nasus and Veigar to be not infinitely scaling?
Firstly, Nasus is considered a fairly weak pick at the moment, last I checked. Which is not to say he's underpowered so much as underpreforming.
Secondly, their scaling is a unique mechanic that is not used by very many characters.
Thirdly, the only reason why I would agree in the SLIGHTEST that something needs to be done with Veigar is because being given free AP with champion hit instead of earning AP with CS was not something that should have been allowed.
What do you mean jax? You think he is op or something? lol
Balance is an ideal that can't truly be reached in a game like this. The best that can be done is to keep striving for it anyway.
Maybe to up the sales to keep the company afloat. I dunno.
STFu, listen the point of the game and patches is to keep the game ever changing and at the most stable point of balance based off the community's feelings.
Unless the Melee champ is broken you should not want to battle ranged
Or you could stop crying about champs that are fine, if not weak.
It will never be balanced
