My Storm Crux (2K with lane shine) is so lazy on the backend. Is there another asymmetric ball out there that can handle a little more oil than my Crux and has a more sporty reaction on the backend?

I've uploaded a photo of my Crux showing the layout on it.

Would a Dream Big be a good choice?

The Lock and Snap Lock are both asymmetricals that have more on the backend than the Crux.  That is if you want to stay Storm.

Couple things though.  When was the last time there was an oil extraction on the Crux?  Secondly, are you sure there is heavy oil or is it that the ball is dying before reaching the backend from there not being enough oil in the front part of the lane?  High end balls tend to need maintenance more often simply because the dulled surface stronger covers soak oil faster than say a polished lower end ball.

EX:  I had a Columbia Disorder that rolled great when the surface was a fresh 2000.  Once I got about 6 games on it; the ball started getting lazy.  I literally had to put a fresh 2000 on it after each league night.  Some covers can be really touchy.

I have not had an oil extraction done yet and I am sure I have a good 25 games on it.
Thanks too for the note about the MB placement.  I will keep that in mind going forward when getting an assym drilled.

If bowling on a THS, you might consider a surface adjustment. Possibly 4,000 or 4,000 with polish will liven the ball up. Strong covers and cores usually demand higher volumes of oil for performance. At any rate, consider cleaning up the surface a bit. Balls loose there OOB surface and reaction very quickly. Although you can almost never return it to a perfect OOB surface, you can follow the manufactures guidelines to refinish the surface to near OOB. I believe they have this on Storm's webpage.

A Dream Big will offer some more performance indeed, however just like any high performance equipment you will begin to see decreased performance after 10+ games. Bottom line, high performance equipment demands more attention to surface maintenance.

Why does it have to be asym?
The Scandal is better than everything atm.

roto grip critical is jump off the spot and hold its own on oil! 

How much of that lazy backend is caused by a lazy hand at release?

No lazy hand here!