"Updating" is not a word I'd choose. Universals are allowed to be used in every version of minecraft, this means you have a choice in what you want to use. It's not something you should just switch too because of others.

As I said before I personally hate using 1.8 and if I choose to use 1.8 from now,  far too many people would never be able to use my skins because they are playing modded servers that are still stuck in 1.6.x-1.7.10

And just like I said before it is unnecessary. Many people enjoy universal because either they just like universals or they can actually use it on any minecraft version.

Just like art there are many artists who have their style and for no reason will one change their style to match another. I enjoy using universals and keeping it simplistic and 1.8 is not the same.

On a side note I would not say they are becoming "less interesting" nearly 10,000 people seem to disagree since they came here and downloaded them over the thousands of 1.8 skins they could've chosen. If I made another universal as good as some of my others chances are it'll do well but I don't care for all that. I draw and share it, plain and simple.