As with any multitool, grab some light machine oil or something with teflon in it. Lubricate each joint area, and flex it back and forth repeatedly for a few minutes, every so often, or over the next few days. Then wipe off the excess oil.
One thing I do about the fulcrum of the pliers is find the section where the inner joint (center circle) will rotate back and forth, not the side that's fused together. Put a puddle of oil over the center joint, then while keeping the pliers horizontal, flex the pliers back and forth for several minutes.
You should notice a change in the oil, where black metal particles will float to the surface as the oil penetrates. After a few minutes you should see minute traces of oil coming out the sides of the pliers - this is a good thing.
I keep working mine in for half an hour or so, and then wipe off the excess oil every time.
Also oil the handle pivot joints for the pliers deployment, these you don't want to get sloppy on - yet are the stiffest on the Leatherman tools. Just keep some oil on there every so often and flex them back and forth when you're bored. These take a long time (days/months) to get comfortable when opening/closing.
Also lubricate the inner tool areas, flex them back and forth and get them well lubricated, then wipe them off.
Next it's to the outside blades, oil both sides of the blades, flex in and out a lot. Also find one blade is a particular stinker in that one is always stiff. Oil it, flex it back and forth.
On the scissors I think we've all noticed it's hard to get a one hand opening of the critter. I've manage two techniques: flipping up and rotating the lesser scissor lever over, or my favorite is to move the lesser scissor blade over a tad and move the main scissor lever over and it snap into place.
The handle slap is cause of the weight of the handles, all them tools in there, and having the largest blades. Have considered trying to find a micro thin layer of silicone and adhering it to the inside of mine. The Wave will do it too if you just happen the flex the handles on the ends - just the wave is 4.5 ounces lighter too.
The MUT had the same issue, but the developers are using a small locking lever that keeps the handles from slapping one another.
There's a Discussion area from the main developer of the MUT over here on the
Leatherman USA Facebook site.
Myself, I have oiled the entire surface of the black oxide version I have. Did not read whether or not yours was stainless or BO. On a limited internet connection so cannot watch videos of everyone's tools, sorry.
I'd also suggest getting the Large Premium Sheath. Find a small mechanical pencil's clip, attach it to the Bit Extender, and clip that into one of the side pockets. Then you can get a small flashlight like a Leatherman Serac S2, invert the clip so you can attach it to the bill of a cap, then clip it into the other side pouch.
This way you'll have an extra reach for with the bit extender, and a flashlight with you for EDC.
Wished there was a small magnet one could purchase, to slip inside the bit extender though. Oh, and does anyoen have a way of making
black oxide bit extenders, or know a method of making one blackened? Am even considering getting a bluing kit!

Just seems silly to spend $30 to make a
BO Bit Extender.