This is very simple, I don’t have any objection with the price of the expansion. It’s expensive, but it’s what it is. You can buy it now, never, or when its price gets reduced.
The fact is that they are gifting the base game with the expansion, right? Well, then I will want my expansion and a serial code for a new account so I can give it to another person. Or the same value on gems, for example. I’m not gonna let them steal that “gift” from me just for being a supporter since Beta.
And if they are not comfortable with this, then make a cheaper option without the “gift”.