My buddy Paul & I often talk gaming systems. We're both tinkerers, happy to discuss how to port Weapon A or Concept B from this game to that. What I find interesting is the "numbers language" we both use.
Paul is a die-hard d20 guy. He's got d20 books out the yin-yang, and he's had a hand in a few of the supplements from the wild n' woolly early days of the GSL. He still enthusiastically plays and supports the 3/3.5e era rules. When he talks about bringing in an item or creature from a novel or movie, his default mode of thought is d20 attributes and rules--STR, DEX, HP, AC, and so on. He's able to stat things for a variety of systems, but he starts by relating it to d20.
I come from systems such as Palladium Fantasy and Rolemaster, which use percentile dice (partially and near-completely, respectively). I tend to put things in terms of percentiles and percentile bonuses. I do this in my head, before I translate it into whatever system we're using or discussing. We know another guy who's hardcore into GURPS--I'd say he's perhaps played 90% of his games over the years under some sort of GURPS umbrella, and when he talks gaming, it starts by being couched in GURPS terminology and concepts.
As gamers in general, I believe we tend to frame things in terms of the system we grew up on, or with which we're the most comfortable. Since many of us started with D&D, D&Disms seem to be the lingua franca for our hobby, albeit a hodgepodge mongrel of one, grabbing from this edition and that into some combined assumption of what D&D is.
I wonder how I'd look at things more differently if I'd started with a form of D&D. Even now, after years of 3.5 and Rules Cyclopedia, when I'm statting things out, it's my Gamescience percnetiles that are dancing through my head. I know when I first really got into the how, what, and why of D&D, some of the terms used were like a foreign language--I didn't share some of the assumptions of others as far as what a certain party composition meant, what a certain monster encounter indicated, or some of the context of terms.
Here's a little exercise: think up a character concept. Then start adding defining attributes. Do you begin to stat him or her in any specific system?