It seems to me plain worng to use AUC years and gregorian days/months. Why not to use Numa Pompillius calendar along with AUC years (with maybe an option to use kalendae, nonae and idus if you want to go full inmersive).
It most likely won't use Gregorian. IIRC then no PDS games have leap days. Can't even remember if the historical ones have correct month lengths, but Stellaris at least has all months be 30 days.
How often do you even add "AD" to the year in your life or speak in terms of BC?
Quite often, actually. As in of the times I refer to a year it's quite a large percentage where I add AD. In general if it's before 1000 AD I always will. If it's between 1000 and 1600 AD it'll depend on context and whether I expect the reader to be familiar with what I'm talking about. If it's after 1600 I assume people will know what year I mean.
I don’t struggle at all to reference time spans between AD and BC dates because I’m used to the calendar system we use...which is the very point of this thread.
Many people do struggle when a span crosses between BC and AD, though. Even in the twitch chat for the Imperator streams there's been several people who've made mistakes in time spans. I've time and again seen people e.g. state that there's 2000 years between say 400 BC and 1400 AD.
most scientists switched to "CE" and "BCE" by now
In some fields perhaps, but I'm gonna doubt it for scientists as a whole. I at least never have seen it used in physics, as it just isn't relevant.
Also, as others noted, then why keep month names and weekday names? Those are religiously founded too and somebody using a different calender could just as well be offended by those than the year.
Personally then it appears to be ideologically driven to change from BC/AD to BCE/CE. If you want to make changes to something widely used then make them actually be changes which matter. And only change if there's a reason for it.
A lot of things came to be for specific reasons, but have existed so long that most people won't know what they mean. I'd wager that if you ask a random person then they won't know what AD stands for.
And should we change the numbers too? Since those are Arabian and that could be offensive to people using different number systems.
In this application, definitely. Very few people have a good grasp of history beyond general "X event happened at some point." The further back you go the less context the average person knows about it. I would guess most people don't have an accurate perception of when events took place past 100 years ago, much less over 2000. Of course they can subtract numbers, but remembering that's who BCE works is not natural to the vast majority of people.
Indeed. In my experience most people don't really have much much knowledge of history before the 1600s. And for Americans it seems to be the 1800s which is where the general knowledge starts trailing off.
didnt know you are lurking here. 
