I agree, the EX2300 is a bit too limited compared to previous platforms. I also find it quite strange to go this way.
On comment regarding dot1q and q-in-q. That's not the same :-) dot1q is trunking of vlans with one tag, q-in-q is multiple tags on the packets. As I remember the chipset used in EX2300 does not support Q-in-Q so it will not be a feature added later on.