Agreed that developers should do what works for them; that's how most innovations happen. It's easy to get trapped in the game engine, adding mandatory RL features, until your system is too complex to add the nifty features that would make your game unique. Although I think making plans in advance is a good idea, I say go with the flow. Personally, I couldn't care less which tool is used to make a game, as long as it's system agnostic.
What interests me more, is your thoughts on what a RL/IF hybrid might look like. While I think good writing is important to a game, stuff like elaborate room descriptions can easily become entertaining (or even mind blowing) the first few times, and then something you <more>-surf through, once you know the drill. ADOM suffers from this.
I think the most common pitfall in this admittedly very unexplored area, is to add fixed IF content to the procedurally generated RL dungeons. What I feel, instead, is that the roguelike genre is so great because of the randomness/replayability, and to really take advantage of IF-like features (such as a storyline, or puzzles), you should ideally tie it up with the principle of randomness, in a meaningful way. If, in every game, you have to visit the librarian to get the magic book you need to solve the sphinx' riddle, gameplay can easily deteriorate into "grind dungeon A, 'c'hat with librarian, grind dungeon B, 'c'hat with sphinx." On the other hand, a lot of storyline could be generated procedurally (with great difficulty, of that I assure you), using some narrative templates and narrative memes. One story template might for instance require a helper, a tool, an antagonist and a difficulty to overcome. The template itself would just be a story with holes in it. But pretty soon, you would want the memes used to fill these holes to conain even smaller holes that can be filled be even more randomly chosen content. Let's say the helper might (or might not) be unavaiable, for a numer of (randomly chosen) reasons -- he might be stuck in jail, and you need to get him out. Or some other problem preoccupies him (a quest to solve) As far as I've understood, Gearhead goes a bit in this direction. I've played it only a little, and it looks interesting, but I can't stand mechas! Legerdemain, while an excellent game with a great atmosphere, mostly plays fixed content.
This turned out to be quite a rant. The original post touches on one of my personal hobby horses, as it were. I'm sure you have entirely different ideas about all of this.
Must go to sleep now,
Minotauros