Flatten is grayed out in pro.  To my knowledge, this is the first time that SolidWorks has grayed out a tool in pro that can be used to making parts.  It's like requiring an upgrade to premium to use the loft command.  If you look at the feature matrix the additional capability of premium (over pro) are specialty capabilities:

1) Motion Analysis

2) Structural Part and Assembly Analysis

3) Life-Cycle Assessment (LCA) for Environmental Impact: SOLIDWORKS Sustainability

4) Routing of Pipes and Tubes

5) Routing of Electrical Cabling and Wiring Harnesses

6) Routing of Rectangular and Other Sections

7) Assembly Level Cost Roll Up

8) Advanced Surface Flattening

It seems to me that number 8 stands out as not belonging in this list.  "Surface Flattening" is a design tool just like Loft, Extrude, Sweep, Offset etc.  Whereas items 1 - 7 are capabilities that are like one another and are not needed for designing in general.  It seems a shame to deprive designers with Pro this one capability or force them to upgrade to premium to have access to item 8 when they don't need 1-7. 

Don't get me wrong I'm very happy to see Solidworks add a new amazing feature like this.  When I discovered the new command I initially thought it was grayed out because I didn't understand how it worked.  I looked up tutorials about it and got really excited to use - my imagination was working overtime coming up with all sorts of cool ways to use this feature to support my design work.    But then after watching the tutorial videos, I was all set to try it out, the wind was sucked out of my sails when I discovered that it was not available in pro (and I could not justify spending the extra funds to upgrade to premium). 

So I humbly request that Solidworks consider making this feature available to pro users.

Am I I alone in feeling this way - maybe I'm just too greedy and want something I should justifiably pay more for?