I think this might have been done as a small discouragement for mercing. Some people like to have a higher number up there, and some people might take pride in having been with their alliance for a long time.
I personally don’t care at all about this new bit of info, would’ve rather had something else show there (e.g. playtime in total, highest titan damage, highest cups ever - anything else useful for either recruiting or I guess something that I could see people could take pride in more than “i’ve joined and never left for X amount of time”). Hope others like it more though, don’t always have to like everything and it sure does no harm