Doorman is shit.
His 1 and 3 are EXTREMELY slow, so you have to be point blank to actually use them effectively. They do good damage tho
His portal is SHIT and it's mostly a massive map issue, there's so many surfaces that you can't use portal on and the map just is not built for you to be able to use angles in convenient or smart ways.
His ult....it's VERY good to have some kind of full disable like this but besides that...it's shit and there isn't anything interesting you can build around it since enemies only take damage after leaving (whether on time or not), there's no special synergies you can build around other than lighting scroll, I guess.
His gun is maybe the worst in the game? It's literally a worse Wardens where it has terrible velocity and shoots super slow.

And realistically, I don't think there are that many good plays you can make with the portals besides what would be the rare cart into portal into tower.