Hiya!
Oh absolutely!
I primarily DM and I absolutely LOVE the whole concept of an RPG game system. I've written one to almost completion (it's totally playable, and my and my group have played it; it's in the never-ending 'tweaking phase'

), two others I tinker with off and on (one is VERY 'story/narrative oriented' with an eye towards Player involvement in world creation as you play; the other is a sort of odd 2d12 based system with other dice being the Ups and Downs, determined by a skill/stat comparison), and one I'm still putting into digital form. That one is one my best friend and I "whipped up in 15 minutes". Literally. To prove we could make a game at least as 'fun' as Rolemaster. We succeeded...easily! (it's....uh....lets just say "mature-child humour oriented"; silly things we found funny...stupid names, absurd concepts, just outright nutty stuff).
I pick up new systems like I pick up, uh, dice. Yeah. Who doesn't own at least a dozen different sets of dice? Go on, admit it, we're all gamers here!

Anyway, I have a fondness for the lesser known or systems, as well as anything that is a Generic Framework (e.g., Masterbook System, SilCORE, even GURPS...). I have probably two dozen "worlds/settings" or "conversions" using these other systems and popular ones. Trying to see what effect a systems mechanics and baseline-assumptions have on another game system/setting is just so dang enjoyable to me for some reason! For example, taking the "Savage Tide" Adventure Path for 3.5e D&D (from Paizo's Dungeon Magazine when they did it), and then 'converting' it for use as a Call of Cthulhu 'Adventure Path'. Or taking the "Age of Worms" AP (also from Paizo; for 3e) but 'converting' it for use in Star Frontiers. That kind of thing.
Suffice it to say, yeah, I'd consider myself an "expert" or "professional", in terms of knowledge and capability. I just absolutely LOVE tinkering and learning new systems! And after being a DM for 40 years (I'm 50...started when I was 10), I
still find new things to create. Only in RPG's can you do that!


So when one of my friends/players asks, "Hey, you wanna run a game of Star Frontiers, Call of Cthulhu, Dark Dungeons, Dominion Rules, or SUPERS next campaign?" My answer is always "Yes".
^_^
Paul L. Ming