If I was you I would just buy one soon and if it's a 702 and a router directly behind it doesn't cause interference, keep it.
I say that because I have a feeling that even if you wait until March you might not get a 703 unit. Once Apple states 'in stock' on their website, it usually means they have a gigantic number of them sat in the warehouse (like, thousands)*. Will they sell thousands of an expensive, niche product, that's just had a lot of bad press, over the next few weeks (i.e. fast enough to replenish stock with March-manufacture units next month)? Probably not IMO.
Add the fact that they went from 3-5 business days to 6-8 weeks to 2-3 weeks to in stock and it seems the stock has already been purged of bad models as you suggested.
*For example, if you pick a product that it 'in stock' online and is also available for in-store pickup same-day, you can increase the quantity to 999 and see that the in-store availability switches to 'ships to store' but the online availability is still one business day, making me think there are 999+ in the warehouse.