When you are employed by the business you will appreciate that even though it may seem unfair at the end of the day it comes down to commercial decisions. The business owns the flying and aircraft and will place you where you are commercially viable. Therefore if that is the mainline fleet even though you may not have access to long range flying and additional pay like on the A380 fleet that decision is made by the business for commercial reasons. i understand you would like to be placed onto the fleet to maximise your income but it just doesnt work like that. Thats not to say you wont have the opportunity in the future.
As for the 787 no one even knows how this will be crewed and under what conditions until the information is released by the business and the union therefore i wouldnt worry too much about the 787 just yet no one even knows where the crew will be based.