Sure of course, there are a lot of things they could do, like make the date font slightly smaller than the time font, or change the spacing between the two lines.
The display format also needs to be easier to change, rather than going through several dialogue windows IMO, and probably with a different default format for the date. For example, I think more people would be interested in the day of the week and or a more friendly month name than a year string, since most people know what year it is.
Also make it easier to switch between primary and secondary clocks, like if you're on vacation.
Hmmm.... I will avoid talking about the Settings Dialog, because that wasn't part of the discussion.
As for 1/21/2015, I like it this way. I don't want my PC telling my it is Jan 21 and have it set to 2000. That would be terrible. And just FYI, 1/21/2015 is so much easier to read than some strange Jan/Feb, blah. Not everyone living in USA is born in USA. And internationally, the words are a mess. Numbers are the universal. Just need to be careful with formatting of the local culture. I don't need to understand the language, just the ordering. That's is way easier than trying to translate the local language.
My point being, TASKBARRRRRR..... that's it. And it is clear Win10 gets it. When they do metro snap, TASKBARRRR is there, even in tablet mode.