Two of my biggest complaints with date pickers are that they often don't align correctly for mobile, and a bigger issue is the inability to jump to a given month/year... About half the examples are unusable for something like a Date of Birth field.
That works... though, probably my favorite datepicker (excluding the lack of sizing for phone/touch) is probably the UX for the Microsoft Ajax Toolkit (hate the toolkit, UX for dates is really good). When you click on the month/year title, you get a panel with each month in the year with prev/next, click on the title again, and you get a decade of years with prev/next.
https://ajaxcontroltoolkit.devexpress.com/Calendar/Calendar.aspx
About the only thing I'd do is tweak the styling a bit larger, and display it full screen for small/mobile devices (phone). I always thought it was a very intuative interface.
I made this one a few years ago... don't like it as much as the one above, but it's good for mobile use. The demo only shows 3 years, but it's in a scrolling field like the months. I should really break it up, and make it compatible with the material-ui library... as it is, it works standalone. Next time I need a date picker beyond the browser's date input, I'll probably revise it. Right now, I mostly just use <input type="date" /> and defer to the browser's UI.
https://github.com/tracker1/md-datepicker/http://tracker1.github.io/md-datepicker/