One of my favorite things to do when the game turns itself inside out is to go back and look at the outcasts, the misfits and the discarded toys of the past to see if they have some new application. Shining Spears would certainly fall into that category.
With the improvements made to jetbikes overall (increased turbo to 36" and Jink), Spears are worth a look.
Hammer of Wrath, woohoo! One more attack at initiative 10! Granted these guys aren't overflowing with extra attacks (base profile of 1), so any extra attacks are gravy, even at S3.
Turbo-boosting increases from 24" to 48", allowing you to turbo all the way across the short bord edge. Denied flank, anyone?
Yes they got the power weapon nerf, but so did everyone else. Did anyone ever use these guys to take down terminators anyway? You're better off taking down a squad of 3+ guys.
Oh and terrain is just as dangerous for them as ever... or is it?
That's where the exarch comes in. Forget about the Star Lance for a moment (what does it buy you besides the ability to inflict Instant Death on T4? Can't imagine that would EVER be useful).
His abilities are now more precious than ever.
Skilled Rider adds +1 to your Jink roll and oh yeah you IGNORE DANGEROUS TERRAIN. Hello? Those Long Fangs gotcha down? Turbo across the board right into terrain with no die rolls and sit there smiling at the nervous space vikings as they unload into you with their missile launchers. You'll have a 3+ Jink save. Suck it, werewolves. Next turn I'm coming at you 12 inches, unloading some S6 shooting and getting stuck in. Overwatch is not that big a threat, particularly with a 4+ cover save on top of your 3+ armor. Sure the enemy may go first due to terrain, but at least they aren't shooting at the rest of your army, such as at your precious skimmers.
Even if they decide to assault you first, you're not completely toothless; Overwatch with TL shurikens or the S6 Star Lance. If you were somehow lucky enough to get Foreboding this turn, say from an attached jetbike farseer, so much the better.
Things don't go your way in close combat? Withdraw with a capital 'W'; Hit and Run is your friend. Make an initiative test (just don't roll a 6), and set up for the next charge. Don't forget Look Out Sir for your Exarch so you can keep him in the game.
Sure the Spears are pricey, but suddenly they are a good unit for quickly ferreting out a troublesome squad entrenched in terrain. Very good!