your X1 has half sized pixels dimensions (traditional screens are 96, you have 210), this means the default fonts that shown before for you was half of the default sizes meant to be, on which there's 2 important points to consider:
- we are used to them, and we loved them, because:
- it is better to have smaller fonts if our eyes can read them, so more contents fits on the same screen
By other side, the correct size of the fonts should be 2mm height for shifted (caps) characters, this is the default by apple which im very convinced they did good eye studies for select these sizes 
- in other words, try to measure them (is not easy) and tell me their sizes, I think that after to do a few tests in screens we can reconfigure the new fonts systems to use better defaults based on the dpi's
the idea is to provide readable fonts for everyone, but even better, the perfect font sized (by default) for them without need to select them
win + p (projector) which I think is the same as on windows (useful for people that uses the same keys, like alt + f4 to close lol)
btw why your resolution is not the bigger one? your screen should look better (and then if the fonts / sizes are too small, to change their settings)
yeah that's why we need a generic way to be able to configure all, but let's start with an auto tool and then we will have a dedicated gui 
nope that's the problem, some screens has very small pixels (new ones) and they are unreadable using defaults, at the same time the default has always been 96 and so 157 should be too big and wasted, so the best is to calculate the size of the pixels in order to represent these fonts, but I didn't do any test yet with special computers (maybe in 2 days I have access to the one with the very small ones lol)
yes the tool try to configure it before graphical system, but about screen resolution, we should use always the bigger one, otherwise we would have blurry pixels
