Gonzalez is a competent SS defensively. He's not great by any means. The Reds really only needed competent to get a huge defensive boost and I think he's provided that in comparison to the last few years.
If people were expecting him to live-up to the legacy of McMillan, Cardenas, Concepcion and Larkin, then the expectations were not realistic. Most teams get by with guys like Gonzalez at SS but do so by having plus offense at the corners. EdE's start and the poor offense from his replacements coupled with the pure blandness of the 1B platoon says the Reds can't carry that right now. Luckily, Gonzalez power surge has been a big reason the offense is still middle of the pack right now. I'm betting it won't last. But the answer won't be to replace Gonzalez. It will be to upgrade the offense at the corners. Fortunately, I think the Reds can do so from within by showing patience with EdE and promoting Votto.
I'd turn all attention to the mound where, IMO, it belongs.