Welding is very good mechanic in some games, like alien swarm, its free game on Steam
http://store.steampowered.com/app/630You can quickly weld door to keep them shut and then spend time to reinforce them, to open door you must again unweld them.
Its great gameplay mechanic, but reinforcing doors work s against ramming aliens, not against marines with breaching charge or welder. And from reality point of view I think if you unweld doors, you must destroy sealing, so you risk decompression.
Yes I know, realism is not always good for gameplay and I don't say it must be this way, only showing some different ideas.
As for abusing locking doors, I think its make sense to lock and open all doors remotely to fight fires, hull breaches, went ship etc like in ftl.
But it is soft lock and all doors can be open manually with anyone (except dumb aliens), so if you want secure doors, you must send somebody to lock them manually and then again unlock them. So to open doors without destroying them, enemy must use hacker, which is low them and you can use. Interesting mechanic can be if enemy hacker lock your doors and prevent you from movement.
Anyway we need first see how important gameplay mechanic welding doors is when we get creew management, I hope soon tm:)