A while back, I posted an article examining ubiquity in EDH - the phenomenon of running all of the on-color auto-includes in every deck, and how it made the format seem stale and repetative despite the singleton-nature of the format. Obviously, variety is the point and appeal of EDH as a format. I accept that as why I'm drawn to EDH in the first place.
It's also a great showcase format, where you can easily get away with running cards that are just terrible in almost any other format. In 60-card Magic you probably wouldn't dream of running Darksteel Colossus unless you were running Tinker, Shape Anew, or Master Transmuter - essentially any way to bypass the 11 mana cost. In EDH, you'd still probably like to do those things, but it's not unheard of at all to just hard-cast the Iron Giant. In fact 11 mana is nothing, considering Emrakul was being hardcast often enough to get himself banned, despite the steep 15-mana price tag.
So, anyway, I wrote the previous article decrying this trend of running too many staples in every deck, making all of my decks seem like slightly different variations on the same basic deck. Essentialy, every one of my decks was a three-color "good stuff" deck with a few pet cards and on-theme cards tossed in where I could. I decided the best way to remedy this situation was to build new decks with themes that restricted the number or "good stuff" slots and demanded more "on-theme" slots.
I built a Sharuum deck with zero combos (but plenty of synergies) and focused on making it an Aggro/Midrange deck that primarily won through creature combat. I also built a Sek'Kuar deck with a Token/Sac/Grave Pact theme. The Sharuum deck was unimpressive. It did what I wanted it to do, but not so well that I particularly enjoyed playing it. The Sek'Kuar deck was a good deal more fun overall, but it was too dependent on sticking a Grave Pact to do much without that Enchantment. Gradually the fun wore off when I realized I basically never won a game without Grave Pact.
This little experiment might not have been a success, but it did prove very enlightening. I realized that there was a tangible upside to the ubiquitous nature of "good stuff" builds. You see, if your deck is designed to do one thing really well (like control the board via Grave Pact tricks) when you're allowed by opponents to carry out your Plan A, you'll dominate nearly every time, but your deck is easier to thwart. Your opponents will know exactly what you're up to, and will know the lynchpins of your strategy, thus can use pinpoint answers to severly cripple your game plan.
"Good Stuff" decks have an appeal based on two principals. First, they are jacks of all trades, and can do nearly anything and everything you'd need them to do. Second, nearly every business spell in your deck has potential to be a must-answer spell. This makes it harder for your opponets to disrupt your whole game plan by killing one or two specific permanents.
There is a big difference between running Mirari's Wake because it's good in your deck and helps your overall strategy, and building your deck around Mirari's Wake. I've tried building around cards in my deck that aren't my general, and it's been pretty much a failure every time.
That's not to say I don't like to have a theme or strategy at all. All of my decks have some basic underlying purpose. but I try to find themes that are broad enough that they leave room for a lot of high-powered spells and aren't easily disrupted by spot-removing a key permanent. If there IS going to be a lynchpin to your deck, it should only ever be your general. My Rafiq deck basically needs Rafiq to win usually, but since he's my general, that's not a tall order for the deck. Almost every card in the deck is a two-card combo with Rafiq so it really doesn't matter what I draw, or in what order.
My Sek'Kuar deck was the opposite. It had a very specific theme and battle plan, and once my opponents had seen the deck in action once, they new exactly wich permanents were "lynchpins" and which were just good stuff. They'd go after the lynchpins first, and I had to just hope the "good stuff" got me there, but it rarely did. Partly becuse there was less of the good stuff than my other decks, and partly beause the good stuff I chose for the deck was still at least sorta dependent on the lynchpins to be really effective.
Since then, I've disassembled the Sek'Kuar and Sharrum decks, and built a Zur deck and rebuilt my Rafiq deck. Even after getting bored with Rafiq and taking it apart, it was still only a few short months before I grew to miss it dearly. I'm also highly considering rebuilding my Vorosh deck. Both decks have themes and run cards specific to those themes, but both are mostly just "good stuff" decks with a light theme tying them together. Vorosh in particular has no single permanent that is crucial to the deck - Genesis in the 'yard is the only real "lynchpin" but I have enough redundant recursion that I can live through multiple Bojuka Bogs.
So where does this leave me? Well, it seems to me that decks like Sek'kuar, that want to do a very specific thing or set of things are more fun than just a random "good stuff" deck - IF your opponents let you do what it is your deck is designed to do. But once they learn what you're up to, they'll be in a much better position to counteract your strategy. On the flipside, Good Stuff decks only have one real theme: cast powerful spells. That's a much harder strategy to disrupt. So while Good Stuff might get old from time to time, there's a reason it's called Good Stuff...
The key is to balance linear strategy or theme with random powerful staples. You need both. How much of each you need, what the right balance is, will vary from metagame to metagame. But it is important to find that balance, because too far one way and you won't have any fun seeing your whole game flushed away with a single Krosan Grip, too far the other way and all your decks will start to look and play exactly the same and you'll get bored.
For me, the balance seems to be that I can push my theme as far as I want, provided I don't have any sort of lynchpins for success, especially ones that are easy-to-remove permanents. If you think your deck NEEDS Grave Pact to win most games, that's a problem. If you NEED to stick a Mimic Vat to win, you're going to loose a lot. If your deck is simply BETTER with either of those cards, but fine without them, you're golden.