Why insist on throwing crumbs to the community and take away set 11?
Really the people that aren't happy because everyone has access to set 11 should be ignored. Because they would also be unhappy if cards would be more accessible, which is the solution to this game's problem.
Also whats worse is that it's damn clear that once you give something you will have a really difficult time to take it away ...
Every time something was getting nerfed (for good reasons) there were always people firmly standing against it. There were players that clearly expressed their concern about the removal of set 11, simply not coming back if it was removed and the main reason for that are the past events.
Now let's go further, deep into irrelevant detail, to point out the rates at which some here suggest to advertise at.
Take the prebuilt promotion to advertise. 5 $ for 30 cards.
There are 200 cards (first two sets) + 9 x 60 cards (the other 9 sets) + 2 x 4 x 10 cards (2 for each sphere for each EX set) = 820 cards total without counting the extra miku and few other EX cards and the unobtainable special set completion rares.
820 / 30 = 273 (here 30 is number of cards in a deck or a prebuilt) and 273 x 5 $ = 1365 $
1365 $ to get as many cards as there are in the game. Just to show the price for prebuilt might be good as an idea to buy a good deck, but not when you try to advertise or make a promotion.
Also take into account those decks are decent at most, i bet they won't be top meta. They won't include 5 stars, not even 4 stars, actually most will be 1 stars, some MIGHT BE 2 stars and few 3 stars! 1365$ is just the price you pay to get 819 cards at prebuilt rate! Wonderful?! Why not go ahead and add this fact along with the add/commercial?
It's not something the game can be proud of or brag about. The prebuilt will be weaker with next OP cards release and there will be no guarantee the next prebuilts will be worth buying even if the current one is.