Not 100% sure what you are saying?

it was the last sacred shard this year, I was hoping to get a hero with which to make a brutal boos and nightmare clan team, but it seems I'm out of luck 

Why do you open shards when there is neither a fusion running nore a 2x chance event?

it was the chance x 2 legendary sacred 

No, it was not. It was an event giving you an extra legendary if you pull any legendary. The chance to pull the (first) legendary was not enhanced. And unless you can open an infinite number of shards, that's not the same, as the outcome of your shard pull proofs. 

The chance for the outcome "no legendary" is exactly the same as allways during these type of event.

ok, I hoped during this event to have a chance, I only had 3 sacred shards, twice in a row Gory fell and now Alaric, if they are sacred shards at least to have a chance at an epic hero of category A, not only the weakest heroes, and the smaller Plarium implements new heroes, the better the chance of a good hero 

Unfortunatly you can't have influence of what kind of epic you get - good ones or... less good ones. 

Buuuut... i must say that i often do the same like the OP regarding sacred shards. Because...

•  even if "single" chance (6% chance to get a legendary) it is still 6 x higher than double chance on ancient shards (0,5% vs 1% during 2x). Of course you can get even 12% chance if you wait for the double chance event but still..
• and even if you get the worst possible, its still   an epic and there are some  fantastic epics out there which can help you progress somewhere, doom tower, fw etc. (i still miss some really good epics: Rector Drath, Tayrel, Seeker - just to name a few...)

But yeah OP... i can feel your dissapointment, happened to me as well many times and probably we are not alone with this issue.

3 is not that many.  I wish you better luck in the future.