For most end-users, it most certainly is world-corruption. You're expecting end-users to be able to a) read a crash log, b) understand what happened, and c) fix the problem. You are vastly over-estimating the average user's technological expertise. Case in point: All the many, many crash bugs which are simply ID errors that can be fixed in config files.Incorrect. Crashing the game != corrupt world. Where as the way Forestry and now Azanor has gone about it, it may very well lead to corrupt worlds. Yes, removing a mod does give invalid ID errors. However, it does no damage to the world other than removing the items that no longer exist. (I've done it myself tons of times. Heck, the downgrade from 1.6.2 to 1.5.2 had some interesting "invalid minecraft IDs" but in the end I had no issue.) Now, once in awhile one might come across invalid TE's. However, those make no difference to game play. (If it bothers you that much, just put a block everywhere the invalid TE was. It should refresh and remove it.)
Again, you are assuming too much technological expertise out of the end-user. I actually understand what you are talking about. Unfortunately, not everyone affected by this problem would. In fact, most people who are affected by this problem would understand to do these things. All they would know is that suddenly their game stopped working, and they can't get it to work again.On another note, once in a while you will come across a mod that will cause a crash upon removing it. There are two possibilities:
1) You removed the mod responsible for the structure of your house. (Nothing I can do about that).
2) Or two, you removed a mod that had liquid in your world. In this instance you have two options: 1)
Open up the Forge Config and tell it to remove errored entities on next load. Or 2) Just log back on, and remove the pipes that contained it. Containers of the liquid should just void out automatically, if it doesn't and causes a crash, just void it out using a void pipe. (Or breaking the block that contains the data.)