Where did the old optimizer go?

what happened to the old optimizer that showed what my current gear had far as stats and what was needed to be optimal?

It’s still there. The only section we removed was the “gear check” section that would optimize only gems and enchants - it became somewhat obsolete with how the game has changed. You can use the Best in Slot section for free to see ranked items for every slot and ranked lists of gems and enchants.

To get suggestions for your specific gear, you would use Best in Bag, which is part of the premium subscription.