Let me preface this by saying I'm not strongly wishing for anything -- as a fellow programmer, I'm more than aware of the cost of writing more code! And also aware that configurability is not panacea -- I'd rather see it as a fully opt-in mechanism, such as a mod one has to install or otherwise ignore and be unaware of.
However, I am also someone who greatly enjoyed support beams in TFC, both because they provide verisimilitude and because they have a reason to exist in terms of mechanics. Overall, when I played TFC the support beams added to my enjoyment and assisted my suspension of disbelief.
At the same time, I must admit I was never convinced the cave-in mechanic was as good as it should be; as previously mentioned, the inevitable self-destruction of caves is a very unfortunate side effect of the TFC implementation, and I would love to see it somehow avoided in any theoretical re-implementation. That said, I haven't given it much thought beyond "it should be better", so no suggestions come to mind yet.
Regardless, I would like to support the idea of having structural supports that are meaningful to gameplay in some way.
I have a few specific points to make in response to the above, as well:
To clarify how it works in TFC: the Minecraft engine has the same limitations (with good reason!) -- simple blocks like stone are all one instance, therefore all stone is either always or never affected by gravity. TFC's implementation is to replace the blocks that should collapse with cobblestone blocks of the appropriate material; cobblestone is affected by gravity and leads to the observed behavior (of a cave-in). The support beam effectively cancels the cave-in mechanic's effect: if a block at position X,Y,Z would have collapsed (i.e., turned into cobblestone) but it is within range of a support beam, then it is simply left alone.
Please don't forget the time spent maintaining the code that makes the system work: bug reports, related code changes -- it all adds up, and opposing it is a similarly weak argument of "I kind of liked having that mechanic". Overall, I'd rather spend a modder's time than Tyron's, if anyone felt up to the challenge.
