While I agree that the 10X/15X odds are terrible, we all play the game and Plarium has not decided to give us anything better (yet?!?!).
Once you reach a certain point in the game, very few champions will actually make much of a difference on your account, and TBH, the longer you play, more and more champions are nothing but Faction Guardians, Vault Guardians or Token Trader Points...so, you save your resources to do fusions & events, and you pull shards when there is a boost on a toon you might have a bit of fun building & using.
I have missed countless boost toons, and it is infuriating to get your 5th Astralon, 3rd Astralith, 4th Roxam or 4th Pinthroy when you are pulling for Duchess, Elva, Kimi, etc.
However, I have pulled Siphi, Firrol, Glaicad, Sicia, Lyssandra, Queen Eva, Amoch, Zaharis, and probbaly some others I don't remember while they were on boost....
Most important though is to view shards as currency to power fusions and events, and not as something to pull willy-nilly every time there is a 2X or an attractive 10X/15X looking for that dopamine hit. Saving Resources and using them judiciously allows you to build a Roster over time that will carry you to end-game.