Ghillieman - go check out my thread 'Gear & YOU - an illustrated compendium', notably, my first post. Gives you something to think about.
I have a Diamondback Tactical RBVP which is basically a Paraclete RAV, which is the same idea as an Eagle CIRAS - they're not lightweight, and they're very cumbersome. They get verrrrrrrry hot.
It's basically the same thing as the OTV, that you have. You would really be buying the same thing, in theory.
For your intents and purposes, Vince is correct.
I have worn the Paraclete RAV and Eagle Industries CIRAS quite a bit, with the soft armor and plates (the latter was my body armor in Afghanistan), as well as a CT plate carrier in the ghan with ESAPIs and soft armor backers.
For just playing airsoft, a plate carrier will do, but I recommend going with something like the chest rig Vince has. You just need something to carry your ammo, water, and items to sustain you for a couple hours.
Clear some floor space and lay out the necessary items you need to carry for an all-day game. Then, think of where you want these items and choose a rig accordingly. More times than not, a chest rig will do just fine.
That said, I wore a CIRAS for airsoft, and liked it. It's just not the lightest, or the most breathable option for carrying a few mags and a bag of BBs.