Lack of Build Up

Scott,

Can you remember a single Wrestlemania where the top three matches were built up so poorly.
All three top matches (Reigns/Lesnar, HHH/Sting & Undertaker.Wyatt) have the same problem.
1) 1 participant not appearing on tv regularly if at all.
2) No hatred or real rivalry between the participants
3) The fans don't care about the result.

With 1 week left to go. Is there any way to salvage this buildup?

Roman Reigns suddenly develops the power of time travel and thwarts the Kennedy assassination?  
I think Wrestlemania 13 might have been worse on top with non-drawing Sid defending against Undertaker in a foregone conclusion, but at least there was intrigue around the Bret Hart stuff there.  11 at least had a storyline behind the top two matches.  12 was pretty weak but clearly people were still invested in Shawn Michaels as a challenger.  
I do have to say that at least they're making an effort to sell Sting v. HHH as a big deal, even if the result 100% doesn't matter, so there's that. 

Smackdown is Useless (and lack of continuity)

What do you think is the reasoning behind WWE putting zero emphasis on Smackdown? I understand it's the B-show but shouldn't there be some kind of reasoning for fans to watch? For instance, how about after the Rollins heel turn on RAW, Michael Cole mentions watching Smackdown with the hope of hearing an explanation. Or why can't they book a match for Smackdown and run an angle on RAW to set it up? One of the main issues with the booking nowadays is the total lack of continuity on what is supposedly an episodic TV show.

​And then they're like "What do you MEAN you don't want to pay $470 million dollars a year for the rights to this show?" and act all surprised.  
But yeah, Smackdown is pretty specifically ignored by Vince most of the time, and for kind of good reason, as ratings hardly seem to deviate one way or the other based on storyline stuff.  For a while they were setting up matches on Smackdown, but then they would totally ignore it and book something different by the time they got to the show.  At this point it really serves no purpose besides extra TV rights fees, much like Main Event and Superstars before they both got canned.  ​