The only viewports we actually see in TOS (from the inside) are the two small squares ones in Conscience
, and the slightly larger rectangular one from Gideon
(which also features an external shutter, meaning it could be hidden from the outside most of the time). That being the case, we've no actual evidence that the "windows" on the TOS-E are anything of the sort. So, what are they? - massive sensor arrays perhaps? It would help to justify why there's so many of them on the Engineering
hull (hardly the place for stargazing, IMO).