Plate carriers, soft armour and any sort of nylon rig on the torso are all pretty much the most effective form of insulation there is. They're not breathable like a high end outdoor jacket, but if you have a reasonable sized PC or chest rig you'll find that keeps in plenty of warmth when running about outside in the winter. Personally it's the extremities I worry about, it varies person to person but my hands just don't seem to have the blood flow of a normal human being so I have to wear some good gloves during the colder months; something often overlooked is that a metal handguard on a rifle will also sap any heat in your hands right out of there. I made the mistake some years ago of skirmishing in December wearing gloves designed for the desert (they looked good, but they had actual holes built in to the design) and holding on to the rail after an hour or so I wasn't doing so great. Tucked my hands inside my PC which started warming them up quite nicely but I wasn't far off spewing when the feeling started coming back. Interestingly I've seen a very similar occurrence many times in a different context, my dad's been in to windsurfing for decades so as a kid I'd often go along for a day/weekend and they didn't stop the events for winter, so combining the general air temperature with a fair bit of falling in water you'd get a lot of blokes coming back indoors on the verge of tears with the pain in their hands as they warmed back up. Not to say this is a common occurrence but I thought I'd throw it out there for consideration, might be pertinent to somebody out there reading.
If you want some upper torso that's modern looking, comfortable under gear and keeps in heat check out the Propper UBACS (UK tac have them). Considering they're a garment that's designed to keep you as cool as possible in the heat, the Propper ones (unlike every other brand I've tried) are made of comparatively thick, heavy fabrics. Makes them much worse than their competitors in the summer but a very useful winter garment.
Apart from that, if you do look at shoftshells (which are popular for a reason) I'd strongly suggest playing a game in some other types of insulating layer before making a decision. People tend to equate jackets with being heavily insulated but there are a lot of options out there when it comes to tactical gear. Some are deliberately just a thin layer to keep wind and rain off while allowing sweat out.. slightly better than a fleece or BDU shirt anyway. The thicker the lining in a jacket the better it is for stationary duties but the more uncomfortably hot and sweaty it'll be when you exert yourself.