It seems to me stuff like Gremlin's main usage would be for macros.  You don't need to consolidate to 1 controller for most sim type games that I have seen.
Although having said that, the one thing I miss from having a full X52 is the ability to do shift states between the throttle and the stick.  As it stands now with me using an X52 throttle and a VKB stick, I can't do multiple-button macros between them, it would either need to be both buttons on the stick, or both buttons on the throttle.  
I wonder if I could get that functionality through Gremlin.  I don't really have a pressing need for it, but it might be ok someday, or maybe my throttle needs to have an "accident".  

I haven't even touched the profiler for my VKB stick.  I was proficient with the X52 software, but the VKB one is frankly terrifying.  I was reading the documentation for the stick as the profiler was installing, and funnily, I got to a line that said, "The VKB corporation was started by a group of engineers that split off from <another company I can't remember> just as I launched the profiler, and I looked at the screen and thought, "Yup.  This was most definitely designed by engineers."  
 
 
Wiley.