Mostly what you said. "Barrels" room trait'd be nice. And a possibility to spend RL ammo searching for hidden rooms :)
Are you referring to a remake of DoomRL? I'm talking about remaking Doom: Semper Fidelis. If not, I'm not sure what you mean by "Barrels" trait and "spending RL ammo searching for hidden rooms."
No, not DoomRL. Although barrels in the original Doom were much less "dramatic" than they are in DoomRL, they're still somewhat of a hallmark of the game, IMO, and would be a nice addition. Consider a cost in Time if you decide to be careful and strategically detonate them ("when the monsters get close"), as opposed to a cost in Health if you decide to rush the room, blowing everything up quickly and taking some damage from the barrels in the process. Of course, the benefit in each case would be the opposite, i.e. in Health and Time respectively. Use of certain weapons might alter results, considering the melee chainsaw and the anyway-all-destroying BFG.
Regarding RL ammo, this probably better fits Duke Nukem. I'm talking about secret rooms which require a certain spot being hit to uncover. This could also be chained to the barrels, where you must first spend Time to avoid hitting barrels while killing the monsters, and then spend Time and/or ammo pushing barrels up against the walls/into slots/who knows what and then possibly shooting them.