I second Sharks opinion - explodes/Immobilized result on a walker is just horrible, FuriosoLibby has no Squad to hide in!
Especially if you are looking for competitive games it probably isn't a wise choice.
Anyway some advice:
I recently used the Furioso Libby in a few Friendly
games and it was very Strong. The Force weapon hardcounters Monstrous Creatures which BA IMO have troubles killing.
However since the Furioso Libby is very fragile compared to its point cost, it can't afford to stand around for a turn where it can't charge. Basically it requires you to buy a Stormraven Gunsip
to deliver it. This does two things for you:
1. Hopefully you get right into melee, best case against some MC which you onehit with Force at I 5
2. It keeps the Dread off the board for at least 2 turns, which you should use to remove enemy anti tank units that can easily kill it.
If the Stormraven goes down while the dread is inside, you're doomed
Great psychic powers for it IMO are:
Quickening (BA-Primaris, so safe to get... at least you get as many attacks as regular non-BA Dreads with it)
Electroshield (Fulmination if you roll a 1 - suddenly you have a super resilient Dread 3++)
Remember the Flibby is a character and can therefore issue Challenges!
Additionally i recommend running a second, normal Librarian alongside the Furioso since you get Warp Charges even if the Furioso is still inside the Stormraven and you may need more dice to reliably get off at least Force and Quickening the turn you go into melee with that damn Riptide you hate so much