Don't you think it's a bit off concept if you want to take full rewards of the 2 year celebration of the game if you are around for only 1 month or so?
Also, this game is not about 1 month, reaching endgame takes 9 months to 1.5 year if you don't pay. Take your time and enjoy the game.
5-10 shards for people that were close but didn't make the fusion is just fine for this circumstance. If you made only 60/100 on a fusion hero, that means you were really new at that time. Happened to me, happened to all (I've also missed other important classic fusions like Rotos, Tormin, Maulie etc) but I didn't have the nerve to complain after playing for only 2 months. I wouldn't even know at that point if I'd continue playing after all. So why would I even bother then? Just enjoy the game and you will have more chances for legos later in the game.