I don’t know what your workflow and style of music is, but in regards to your question about new instruments; I think that the Halion Sonic SE instrument is worth a couple hundred bucks by itself.
And while I’m not a guitar player, my family and friends who are have really been tickled with the VST Amp Rack. In fact, I’ve played more guitar this past week than the last five years combined! (just messing around with the Amp Rack).
I’m going to make an assumption from your screen name that Remixing and audio mangling (and DJ style stuff) isn’t a big part of your sound? (appologies if saying that rubs the fur the wrong way
That said, the performance controllers they added to Loop Mash in this release have (IMHO) taken if from being a curiosity to being a usable creative tool.
Granted, what it does is fairly specific. Not many folk artists or traditional Jazz guys using (I assume) but for what it is, these new features really made it useful.
There’s a lot more that I’m very pleased with. I started with Studio 4 several years ago so I have some appreciation for your working environment. I offer that only because the overhaul that Media Bay received in version 5 is worth the price of the upgrade.
I think you’ll be really pleased with the refinements to the workflow and general system enhancements.
My two cents.
PS: years ago I got to work on a very cool Rock CD that used mandolins in place of the usual guitars. To this day one of the coolest CDs I’ve worked on! Recording the Mando-Cello in particular! FWIW!