I'm writing this in a one bedroom at the Nanea (room 8507). Jabberwocky and several others who recommend the KOR-North are absolutely correct. First, Nanea has no studio or one bedroom oceanfronts - so that's not an option for you as a couple. Between North and South, the South studios have what they describe as a "French balcony"...it's enough to step out but not room for a chair or table. Nowhere near the MOC studio (if you are familiar with Napili/Lahaina oceanfront studios) lanais. The North lanais would be the closest to MOCs.
We are new to the Westin Maui resorts (purchased Nanea when it first became available but before it was built) after being with MVC since the MOC was transformed from a hotel into timeshares. We purchased one-bedroom because we became empty nesters and thought buying one-bedroom was all we needed (this was before I learned about TUG and resale options). We also were very attracted by Westin's studio layout which has washer-dryers and stove tops, microwaves, etc in the room. However, we didn't realize Nanea had only very few one-bedrooms and the design of the rooms are quite puzzling. For example, unlike MOC, where the ocean-views are very nice, the room I'm in for example - which is apparently considered one of the better rooms (athough technically "resort view") - has the view of the ocean partially blocked by the ocean-front two and three bedrooms! I don't blame Westin for wanting more 2 and 3 bedroom oceanfronts but they definitely could have made more money by redesigning the buildings so they could charge more for rooms with better ocean-views also (kinda like the Waiohai Beach Club). Also, the Nanea one bedroom has only one sink and the shower is in a tub and to top that, the washer-dryer is in the same bathroom! It's a much larger bathroom but so poorly designed! We have also stayed at the KOR-North and I actually prefer this resort to the Nanea except that my wife says there are too many rug-rats around the pools (Nanea has an adult only plunge pool). Net, from somebody who has significant experience with MOC oceanfront villas, see if you can get WKOR-North. If you want to be assured of ocean-front, may have to pay up to make sure you can get the desired view. Good luck.