You are reading what you want to read.
The 14-30 f4 is outstanding, not just very good.
If the 14-24mm f2.8 is even better it will because it will be the best wide zoom lens ever designed.
Cheers,
Bernard
Make it 14-24/4 instead of 14-30/4 and you could make it even better optically, with the same (or less) size and weight. A lens with a smaller zoom range is always going to be easier to design, and involve fewer compromises, than a lens with a greater zoom range. This is much more pronounced in UWAs and WAs than in telephotos.
To look at it from the other direction, the Canon 11-24/4 and Sony 12-24/4 are both extremely sharp lenses (when you get a good copy), considering how wide they are. Imagine how much sharper you could make them if you didn't have to deal with the extreme UWA end (and, in Canon's case, the mirror box) and made them 14-24/4 instead.
The basic premise is this:
In addition to a monetary budget, you have a size and weight budget for camera gear. Even if you have a cupboard full of lenses at home, you can only bring so much with you at any one time. Within that budget, you want to fit in as much capability as possible. Or, to look at it another way, you want to be able to carry the capability you require with as little size and weight as possible, to leave space for other things.
Every lens design requires compromises. Assume the same final price and start with the base of a slow prime. This will be just about the sharpest, smallest lens you can get at that focal length. The thing is, it's not very versatile - it's sharp, but won't isolate subjects very well, won't gather a lot of light for shooting in very dark conditions and only shoots at one focal length. If you want to be able to shoot at lots of different focal lengths using lenses like this, you'd need a whole arsenal of them, which would rapidly consume your size/weight budget. So you choose lenses that are more versatile, but sacrifice something else to get that versatility, so that your final selection gives you as much capability as possible (or as much as you need) while still fitting within that size/weight budget.
What are these compromises? Make it a zoom and you can shoot at a lot of different focal lengths with one lens, but you add size and weight and lose sharpness. But this can be worth it, since a zoom, although larger and heavier than one slow prime, is still lighter than the whole bag of slow primes it would replace. Give it a larger zoom range and you can shoot at even more focal lengths and have to change lenses less often, but you make it even heavier and less optically optimal. Widen its maximum aperture and you can shoot in darker conditions and isolate subjects better, but, again, you add size and weight and lose sharpness, since it requires more optical compromises to achieve this. Add lens-based IS and you can handhold at slower shutter speeds, but, again, you add size and weight and lose (potential) sharpness. Add macro capability and you make the lens larger, but can shoot smaller/closer subjects.
You could probably build a do-everything, 14-400mm f/1.4 zoom capable of shooting 1:1 macro - but it would probably be the size of a small car and be about as sharp a lens as a wine glass. The thing is, you don't need every capability in every lens at every focal length. You need to decide exactly what capabilities you need, what your size/weight budget is and what gear to bring to maximise your capabilities within that budget. Or you can approach it from the other direction, deciding exactly what capabilities you need, then seeing what gear you need in order to minimise the size/weight to achieve this.
To apply it to the 14-30/4 example, it has a number of compromises. It's a zoom, not a prime, so it's going to be larger and less sharp than a prime in that focal length. However, it has a narrower aperture than primes, so is easier to design from that perspective. It's also going to be smaller and lighter than carrying 14mm, 18mm, 21mm, 24mm and 28mm primes all at the same time, and require far less lens changing.
Now make it a 14-24/4 instead. It's still a zoom, but has a smaller zoom range, so you can make it smaller and sharper than a 14-30/4 zoom. Of course, it is less versatile, since it doesn't fill the 24-30mm range. But you're probably not going to be carrying just one lens - and, if you are, it almost certainly won't be a single UWA zoom. That gap can be filled by your 24-45/4 (or similar) zoom. If you don't need rapid access to every focal length and changing lenses is possible, it doesn't matter if one lens doesn't cover a particular capability if another one in your kit does. (if you need rapid access to certain focal lengths, e.g. as an event photographer, you'd build your kit differently).
In other words, it's not just about individual lens optimisation - it's also about kit optimisation.
Applying it more broadly to lens selection, consider the classic 16-35/2.8, 24-70/2.8 and 70-200/2.8 combination, with two camera bodies. Here, you have a jack-of-all-trades setup. It's a big, heavy setup. You can shoot every focal length from 16mm to 200mm and not require a lot of lens changing. The lenses may be sharp, but not as sharp as primes, zooms with a smaller range, or, potentially, slower zooms. You can achieve some subject isolation, but not as much as with primes. It's a perfect setup for some kinds of photography. If you're a photojournalist or an event photographer and may need to shoot any subject at any focal length at a moment's notice - and getting the shot is more important than getting the perfect shot - it's probably ideal. If you don't need instant access to every focal length and are after more subject isolation or sharper images, it's probably not. You're paying a huge premium in size and weight for capabilities you don't need and aren't using.
What else can you achieve with the same size/weight budget? Say you changed the zooms to f/4. Now you've halved the weight of your lenses and probably have sharper ones, since f/4 zooms, when built to the same standard as their f/2.8 counterparts, can usually be made optically better. You've lost some subject isolation and low-light capability - but you now have extra room within your budget to play with, to make up that deficit. Do you really need subject isolation and low-light capability at every focal length, from 16mm to 200mm, or just the ones where you typically shoot portraits at? Let's say you add in an 85/1.4 prime. Now, within your kit, you can achieve more subject isolation than an f/2.8 zoom setup can ever hope for, while still weighing less. You still have more size/weight to play with. Let's say you want an even sharper setup. So you replace the 16-35/4 and 24-70/4 with a 14-24/4, 24-35/4 and 35-105/4. You've just spent that size/weight budget, but now you have a sharper setup for the same weight (albeit with a bit more lens switching). But now you also have a significant overlap in the 70-105mm range. You aren't shooting events and have two camera bodies to mount lenses to, so you decide to replace the 70-200/4 with a 100-300/4. So, for a similar size and weight to the 'trinity' f/2.8 zoom setup, you now have a 14-300mm focal length range capability, sharper lenses and, with the 85/1.4 prime, more subject isolation capability. You've sacrificed the convenience of having most of your focal length range available at the same time - but, since you aren't shooting events, generally have time to prepare for a shot and can have two different lenses available on two bodies at the same time, might decide that this is a worthwhile tradeoff.
This is where the premium f/4 zooms come in. Make them slower than the f/2.8 zooms and you make them smaller and sharper. Reduce their zoom range and you make them even smaller and sharper. Cover their aperture deficiencies with one or two primes, where you could really use the wide aperture, which will do the job better than any zoom ever could. Or cover the versatility deficiency by also carrying a single 'walkaround' lens as part of your kit. No, it won't work for event shooters and others who need their entire focal length range ready to shoot at any one time. But it will work for many (possibly most) other photographers.
You probably won't have a setup consisting of all f/4 premium zooms, or all primes, or all f/2.8 zooms. You'd likely mix and match them, depending on exactly which capabilities you need, and at which focal lengths. You might even keep all of them in a cupboard at home, selecting your kit depending on the requirements of a particular shooting trip. At the moment, it's hard to do that - either you have fast, sharp primes, fast-ish, sharp-ish zooms and light, cheap zooms, but no slower, lighter, sharp zooms to fill the capability gap.