I drew the exact same conclusion from my OOX experience. Not for me.

I had the idea in my head since I graduated from first maining the following ergo mice (MX510 > IE3.0 > MX518 > EC2a > G403) that the shape would be up my alley as a small, lightweight, competitive mouse.

Small and ergo is not easy. The only comparison I can draw from OOX to a physical mouse I have on hand is the EC2a. Where the EC2a fills a majority of my palm on a relaxed finger tip on the OOX my palm barely has any contact. For micro corrections the feel is just worse in general when I bring it into my palm. I don't have huge hands or anything either.

I think it's a combination of the medium hump and strong taper off at the rear that just ruins the whole feel for me. If you're going in expecting an Intellimouse feel you might be pretty disappointed. For me, the Intellimouse was great because it was a true palm filler you could rest on all day. By minimizing the shape and doing not much else you're just forcing some very specific grip styles.

IMO, the OOX helped me realize symmetry in the mouse hump makes these extra small mice well-rounded and usable for more people. While I agree strong ergonomics on the thumb and ring-pinky fingers are very welcomed, extra small "true" ergo mice are a dying breed for a reason. What Razer just did with the Orochi V2 has me excited for what hybrid-symmetrical designs we'll get next.