Actually, the main thing, other than the regular refurb and drying of the logs and replacing the landscaping is the replacemt of most of the lift hill devices. Last time, they replaced half of the lift hill on Hill C (the large one just before the big drop). They are now replacing all of lifts A and B, along with the other half of C, which includes all new motors and related equipment.
You might find some minor plussing in projection equipment and related items (similar to what Alice in Wonderland got recently).
Forgive me for being a noob, but what is plussing?
"Plussing" as adding on as in a Plus sign.
So the addition of a few new projection pieces in Alice in Wonderland, or the change in the Attic Room in the Haunted Mansion would be "plussing", basically adding some new features without major change.