It's not hard. In my previous post that I quoted, I specifically stated that you can get anywhere from 10-20k/hr in a grinding party.
So, we can quite easily get the SP the developers consider "good"- no problems there. You don't seem to agree with that, but I think the grind is just fine the way it is now.

You can leve or you can grind, but there are fewer ways to do it to get at least 10k/hour, and more ways to screw it up (more so at later ranks. 1-30 is now a cakewalk after patch 1.15).
But you just said it's not hard to achieve 10k per hour? I don't think so either. So you aren't really making much sense here.

If you want to maximize SP gain for 5 hours, you use the exact same method for maximizing SP gain for 1 hour: get a bunch of people with leves and then link them all.
I just told you that sharing leves is better for a 5 hour party than linking them; +100% SP instead of +50%. Leve-linking is detrimental for a 5 hour party because when you run out of leves, your SP gain drops. With leve-sharing, you don't run out of leves as fast, and can achieve more total SP than if you linked them. This is not rocket science and I don't understand how you have such a hard time understanding.

Wasting time is not efficient. Time is always a concern.
This is silly. No, time is not a concern for some people. You can't talk for everyone out there.

No. If you want the most SP over-all, you leve-link. Then when you run out of leves, you find more people who do have leves they are willing to link with you. If you can't find more people with links, then you go grind some normal mobs. This strategy will gain more total SP than a party that just shares each link individually and wastes all of their guardians favor.
This doesn't make any sense. You run out of leves but can still link "them" with others? If you can't find people to link with (=leech, which doesn't work according to you, so this plan is even dumber), you go get inferior SP while the people who share their leves are still getting more SP for a longer period of time, eventually passing the leve-link group by a mile.

I can see what the problem here is now. People don't grasp what is efficient and what isn't and resort to this kind of stupidity and then bitch when things don't go their way. Too bad, because the system works fine.

the difficulty involved in "building a set-up"

In the games current state, yes, it's good enough. There is much more incentive to party than there is to solo. If there wasn't, you wouldn't see so many shouts for leve parties in Uldah.
If you have "difficulty in building a set-up", then clearly it isn't good enough.

You misunderstand. I'm talking about the uselessness of increasing stars if it takes the mob's level over the dlvl 10 cap. Read my blog post that I linked earlier. It shows you how SP is calculated in this game.
Ah yes, I did. And how many people is needed to take a dlvl10 monster down effectively?

The 30 minutes is a waste of time, but once you get a decent party started, it is not a waste of time.
You can solo for 5k/hr during those 30 minutes. What's the waste in that?

I think we're arguing for more or less similar means, it's just that you're calling it "control", and I'm calling it "freedom"
Actually, you are arguing for freedom in solving the problem, while I am arguing for control to solve the problem. Both approaches can take us somewhere, but only with enough control can the developers make the progression easy to understand, expand on the parts that need expanding and create a more tighter community that isn't divided between three+ different progression methods, while S-E has to balance between them for ages to come.

You aren't all about freedom either, but there are no extremes here. Only emphasizing different sides.