it certainly doesn’t make you right, and it does make you a lot more likely to be wrong…
show me how it doesn’t apply. You know nothing about how GD works, you probably do not know how to code, yet you feel qualified to talk about how much effort it would be. That is Dunning Kruger.
Also, you missed about 90% of the work because you have no idea what you are talking about. Just off the top of my head:
What about expansion masteries, can he play them ?
What about higher max level for the char ?
What about new devotions ?
What about expansion items, can they drop for him ? How do you prevent that (here’s a hint, currently not by any kind of switch)
What about item stats that differ between versions (vaniila to AoM, not 1.0.7.0 to 1.0.8.0) ?
If one player who has the expansion opens a portal into the expansion, can he use it ?
And remember, the solution is not a simple yes / no. If you need to prevent something, then you have to think about a mechanism to do so. None of which exist today.
I did not feel attacked, I felt you were clueless, still do