Upload & Sell: On
As to "whose looking" ... publishers & editors of National Geographic and Arizona Highways probably don't get too enthused when they receive landscape images with soft corners that could be shot with a kit lens. My grandmother couldn't care less and will get excited at anything I did. Kinda depends on your audience ... be that yourself, or others.
However, while DOF has some bearing on that, the design of the lens can also have impact on it. Optics are always a series of tradeoffs ... particularly more challenging / noticeable in the WA/UWA ranges. Some lenses are intentionally designed to favor sharper centers (zone A) than corners (zone C), while others are designed to be equally sharp in all zones (A, B, C).
Just because a lens is faster or slower won't necessarily dictate whether or not it has sharp corners. Other issues in lens design such as distortion, vignetting, CA etc. also factor into the cost of "expensive" lenses.
Buying a fast lens (1.4, 1.2) is kinda like buying a dump truck ... if you don't need it, don't buy it. But if you do need one, a wheel barrow just won't do. Many lens designs perform at their optimum @ 2-3 stops from wide open. So from that alone, a 1.4 lens may be at its best around 2.8 or 4. Thus, if you shoot a lot @ 2.8, doing so with a faster lens can put you in a better "sweet spot" of a lens, rather than a 2.8 lens that is on it's "ragged edge" of performance. In that regard, fast glass, isn't always just about shooting it wide open for ultra-low light or uber-skinny dof.
If you are planning on shooting landscapes @ f8 or f11 for DOF purposes ... such fast glass can actually be counterproductive as you may be shooting outside of the "sweet spot" for such a lens. Alternatively, a lens that starts @ 2.8 or 3.5 may have its "sweet spot" around 5.6-8 or 8-11. While this is a general rule of thumb ... a given lens may or may not adhere to it, depending on how the engineers decided to design its drawing style / IQ. BTW, (iirc) noted photographer Galen Rowell shot much with the Nikon 20/4 AIS ... likely to hit the "sweet spot" around f8 (just guessing).
As to your question @ what I buy to get good IQ ... I buy well corrected lenses with minimal distortion, vignetting, CA, etc. that have good resolution and good contrast, and even sharpness through all zones A,B,C. Some lenses are designed to have greater central resolution ... and I have a few of those as well, but note them as such. As to transitions, I have a mix of glass that have slow transitions and rapid ones ... transition rate being a rather subjective matter (as is much of IQ/drawing style).