I don't - because that's not the way to approach 4e monsters. The way to approach 4e monster design is to start with how you want the monster to behave and write that up as powers, almost entirely ignoring feats or other monster abilities. You don't bother looking for feats or spells so the monster does it exactly the way the wizard does. You just give the monster the abilities it needs. You don't start with a list of powers to pick in monster design. You start with a blank page and the setting.
I don't really have much else to say. I will reiterate that I do not think that 4e is a bad system or a bad design. Only that I don't care for it. It's a different approach that doesn't appeal to me. Nor do I think that might approach must appeal to everybody else, including you.
This quote perhaps highlights a bit of the difference. It's hard to tell because perhaps you approach it similarly and are just phrasing it in a way that makes me think otherwise. But it seems like you are starting with how you want the monster to behave. While that does have some impact in the design, I start with what the monster
is.
For example, if I were to design a new dragon I would start with the base dragon abilities - wings, etc., and why and where this dragon exists. Why another dragon? What's the ecological niche, why doesn't an existing dragon fit? I add/remove monsters based on how they fit in the world before I consider their behavior. The behavior is partially based on their nature, dragons are likely to behave in certain ways as a species. It's not a blank page, it's a dragon. It's building off of an existing template. And I absolutely work from a list of powers to pick.
I also don't think of a creature in terms of combat abilities, feats, etc. Abilities are selected based on the concept, and then you can figure out how it might use those abilities. First and foremost, the use of the abilities would be centered around things like how to get food. Not how to defend against adventurers or make the combat interesting for them.
So lets say I think there's a niche for a jungle-based dragon. It lairs in the canopy. It's a dragon so it can fly (and soaring above the jungle canopy is something that seems particularly draconic). So far all dragons are carnivores, so I'll stick with that. And they have breath weapons. Poisonous creatures abound in the jungle, so I like that, but a green dragon already has a poison gas breath weapon. Instead it's a line, really more like a spitting cobra. Many venomous snakes hunt by ambush, using their venom to paralyze their prey. So both their breath weapon and their bite is poisonous.
Because of the dense foliage, it's a very serpentine dragon and has a climb speed. What else would make sense for a magical creature that lives in the jungle? I like
entangle. That certainly makes sense. Right now this is a serpentine dragon, with some serpent traits overlaid on the basic dragon template. It needs a decent food source, but in the jungles of Chult that's easy. Dinosaurs.
Other abilities?
Pass without trace is a good fit. In fact, this is beginning to feel more like a druidic dragon approach. Something neutral, maybe neutral good. So being able to shape change is a common draconic ability that I think fits well here, but instead of a human form, a lizardfolk form seems much more appropriate. So a more powerful ability that seems particularly appropriate would be
awaken.
Its abilities and location also make it a good candidate for a deity-like creature, or at least viewed as avatars of the deities by the more primitive jungle lizardfolk. Which points to another niche that might need to be filled, a jungle-like lizardfolk. Perhaps just a bit of a flavor change from the existing ones, although the lizardfolk in my campaign that live in swamps tend to hunt like crocodiles. In fact, lizardfolk with a poisonous bite would fit the jungle environment very well, and many reptiles have venomous bites, even if very mild. Using their own venom on blowdarts would be interesting as well, and a natural way for them to take an innate ability and build on it.
Another ability that both the dragon and lizardfolk might have is a camouflage ability.
The breath weapon is a combination of the black dragon line and the green dragon poison.
Spells are druidic based, but dragons use sorcery in my campaign (which is implied in the optional rule, but sorcery is different than wizardry in my campaign, not just the ability that uses it).
The camouflage ability is detailed in the bullywug, among others.
As a dragon it has the usual perception abilities (blindsight, darkvision), the usual claw/claw/bite/wing/tail attacks. This is a stealthy dragon, and once I start thinking in terms of behavior, I'm thinking very reptilian. Lie in wait, poison the target and wait for it to be paralyzed (so it's a paralyzing poison, which is different than a green dragon). The handful of innate abilities, plus its spellcasting pretty much finishes it off.
All of this is entirely edition independent. Totally. So maybe I'm wrong, maybe it's not a 4e thing, but maybe just that 4e took so many liberties in changing things from prior editions that I don't like. But your description - start with how you want the creature to behave, seems to me to be the approach that 4e encourages. It encourages cool combat abilities that differentiate the creature from others of its type.
Going back to Matt's video, he is specifically discusses modifying monsters to make combat more fun. "Wouldn't it be cool if...?" And his solution to making this dragon that is somehow boring during this combat is to add abilities to it that make it more interesting in combat. That's what I object to.
If that's not a 4e thing, then fine. But the video was held up as an example of what made 4e monster design great. That video highlights this specific approach to monster design that I don't like. So if this is an example of what made 4e monster design great, then it's an example of exactly what I don't like about 4e monster design.
But a red dragon in my world is a red dragon. If it's a boring combat, that's on me, the DM for not using the dragon to the most of its capabilities, first and foremost being its intelligence and wisdom. That is, the intelligence and wisdom of a centuries-old creature. Not because I didn't think up some cool additional abilities. Really, though, I find it difficult to understand how one can't find a 50 to 100 foot dragon lunging at you to attempt to bite you terrifying.
Monster design to me is part of the world-building process. "How does it fit in the world?" and not "will this make an interesting combat?"