Nothing is “that bad” but everything can be made to be bad, it’s all player perception.
If the majority of players do not like the covenants being locked:
Will the players burn down the servers? I don’t think so.
Will the game lose some players? Maybe/Probably idk what to tell you.
Will the game be less enjoyable than it could for these players? Most definitely.
I did not mean to say otherwise, I just think that some people are forming opinions and passing final judgement prematurely. As you said
If you go into the covenants with a sour taste in you’re mouth chances are you’ll leave with a sour taste in your mouth.
For the record, I’m largely in the “aesthetics and lore only” camp when it comes to covenants.
This.
I don’t like ketchup and mustard.
Salt and pepper is nice, but I want mayonaise with almost anything!
So, easy choice.
Ps; thanks for making Night Fae into Mayonaise, because the above info isn’t even made up… it’s all true. 
But do you want to limit our choice of using other toppings/seasonings?
You personally can stick with mayo, since you like it so much.
Yes. Because your choices mess up the menu. 
The ‘optimalization mentality’ is seeping into content where it’s not really needed. But a lot of players still adopt this mindset of ‘be the best or get out’.
And what I agree with Ion on is that THAT kind of mentality/mindset is taking away from part of what an RPG is; having the ability to express yourself by making a character your own.
So… Since that playstyle is hurting one of the pillars of the genre, I think they’re completely within their right, and actually have a responsibility, to do something about it.
You can still optimize your character in many situations. There just won’t be a ‘one size fits all solution’ to every challenge. And I really think that’s better for the game and genre at large. Yes it’s at the cost of some people’s fun, but imo that’s worth it.
Or to keep to your analogy;
It wouldn’t be keeping mustard from you (for instance), but merely one tiny ingredient of mustard. You can still have mustard; it maybe just won’t taste completely like what you’re used to. Or maybe, you won’t even notice it’s not ‘complete’ mustard at all. 
Maybe we can choose a second topping? I would be happy to be locked into a topping for a month if the option to switch to my designated alternative topping was available at the end of the month if I wanted to.
May not be available when the service first starts but if people complain enough in solidarity the service may halfway through the plan let us choose an alternative topping we can switch to under certain circumstances, like they did with the drinks machine (corruptions). Before we put our glass (gear) in the machine and got whatever we were given (RNG), but it was free. Complaints were made and now we can put in a pound into the machine and choose our drink (corruption vendor).
But exactly what was that business about? Since they let go of “restrictions”.
The thing is, you put the glass in the machine but you got nothing most of the times, or got not what you wanted.
That means that it was meaningless and left us at the mercy of RNG.
Now we’re not even at the mercy of RNG, we’re at the mercy of Blizzard balancing strictly and can only have 1 choice.
If Blizzard decides to nerf our most fun covenant and make it not fun, how am i going to chose another covenant?
I need to sample (experiment) with multiple toppings/seasonings (covenants) to decide what i want to use.
I can’t even do that, i’ll just pick the next and that’ll be it.
A cut and dry decision, no experimenting with different flavors, no nothing.
Just point a finger and get it. This does not sound fun at all.
This made me feel like having fries for dinner!
You sample them whilst leveling.
It simply can’t compare killing some weak mobs(leveling is easy), versus using them in a raid, PVP, M+ or even while doing the dailies at max level as they are scaled more appropriately at the start.
The amount of stats will also vary from when we are weak at the start versus mid patch or end of patch. Covenants will become also less effective or more effective depending on what talents we take at max lvl, which sometimes are different from when leveling.
Basically having a week the abilities during leveling can’t compare to using them in endgame situations.
It’s like you said, just a sample, it changes with what we sample it with.
But why are you letting the skills be the main factor in making your choice?
Why are you not simply picking the covenant which appeals to you most or that you think is a perfect fit for your character’s fantasy?
If it’s about min-maxing/optimizing for you… then I will point you to what I said previously: Choose your topping/seasonings for the next 2 years - #26 by Tahra-earthen-ring
Pineapple. Always pineapple.
All other toppings are for losers and Chelsea fans.
Actually, its Ananas, not pineapple. Silly English people, always going against the flow.
Because the zones are just the zones for me, i’ll visit them all, spending more time in one or another won’t be that much of a time difference barring dailies restricted to that zone.
The mogs are indeed what i’ll want to wear eventually, especially if they will loosen the restrictions.
But i prefer to mix and match different ones toward a theme that i chose, like: Trashmaster, Timelord, Highlord, Patron, etc, i have over 50+ mogs saved, thanks to an addon and can freely switch depending on what i want my theme to be for the week (i change weekly) + different mounts to match the theme. + titles as can be seen by the naming conventions.
If i pick Necrolord, it means i’m just helping(and getting benefits in return) the Necrolords with something. I won’t be a Necrolord Paladin, it’s contrary to my class theme, it’s the exact opposite.
Me being a paladin does not matter in this case, since it’s the same goal that we are working on, i’m not turning into a Necrolord myself.
The enemy of my enemy is my friend works here.
Edit: You won’t have a menu with only 1 choice, it will restrict it, it will make everything else taste lesser than it could.
Naw he founded the Roman empire (according to Virgil…). The pineapple I suppose has taken its place as emperor of the semi Italian food however.
good thing you chose Ketchup for Venthyr, I will definitely go Venthyr and coincidentally I also like Ketchup…
There is just no way for me to pass on Vampire Gothic theme
I hope you finish writing your expansion soon.
I’ve never been this motivated to fight a raidboss.
Pineapple pizza has nothing to do with italian food.
It was an easy choice… vampires would like ketchup because of certain resemblances, i know i do. 