As we all know TNO/II TNC and Fallout 4 are both developed by Bethedsda, I always think it's very interesting if we can play TNO/II TNC as gamemode like Fallout 4.(for convenience, i call it"this game" in my article)
Same as fallout 4, this game is an action role-playing game set in an open world environment, also it takes background in America, but the only difference is that america are ruled by those nazis who won wwii same as TNO/II TNC(not split up like fo4). However, because of intense resistance, the map (as big as wasteland in fo4)where player(play as B.J. Blazkowicz) is in are not fully controlled by nazis, and some place controlled by rebels aganist nazis(just like Caroline did in 2009-version Wolfenstein).
At the beginning, player(B.J. Blazkowicz)meet leaders of rebels who ask player for help(like player meet Preston Garvey, senior officer of the commonwealth minutemen at the beginning in fo4) Same as fo4, after the first mission, player will start to help them to reunite the rebels and fight back against nazi occupation step by step through accept missions from different places.
Unlike fo4, there is no feral ghouls, raiders, gunners or any variant creatures, the only enemies of player in this game are nazis and their supporters and puppets, the american pro-nazi traitors. The rebels are facing harsh living conditions same as wastland's people in fo4 under the nazi's suppression, so player need to freely walk around the map and collect resources in order to keep resistance’s survival and one day fighting back to nazis after they strengthen day by day, like player reunite the minutemen and rebuild commonwealth in fo4.
Similar to fo4, player can build and manage new settlements for rebels at various sites around the map, of course, the nazis will regularly attack those settlements, so player also have duties to help to protect them. Player can ask the rebels for help in any battles if those settlements are mature and powerful. There will be nazis everwhere in different locations, player can chose to kill them and take their weapons, ammunitions, armors and medical items(if there are robots like Panzerhund, Guard Robot or Heavy Robot, you can even take their circuitry or metals, etc), or let them go if player's perks or ranks are not enough(the ranking system are similar to fo4). The excess weapons captured from nazis can assign to your new rebels in settlements, or trade them with black markets(Player can trade materials with black markets, of course, the currency is gold, not caps!!)
These are all my personal opinions, Welcome to discuss XD