I think the softlock is a valid concern. An unwitting player can lose their entire playtime if a boss spawns behind them and, while saving multiple times and often would eliminate this, the loss of that playthrough would undoubtedly sting. I wouldn't be surprised if somebody gave up on the game entirely because of this.
An emergency 'escape rope' item/skill/prayer could get the player out of an unwinnable scenario. Maybe there is a better system.