Creating this topic was a good call, a great variety of mods has been created so far and a certain platform should exist to discuss them.
From what I can see, Yomama, all the features of the modifications that you referenced in your post serve to improve the performance of your game and/or make it more user-friendly. The bugs that are being fixed are minor nuisances and by no means decisive factors in overpowering your opponents in the game.
Also, modifying or even removing objects that you can normally drive, fly or shoot through, such as clouds or tree leaves, shouldn't be a problem. It affects one small portion of your game without giving an overall unfair advantage. It won't help you if you're a crappy pilot/shooter. On the other hand, if you're a good one, it might help you one tiny iota, but not more. Such modifications can notably increase the performance quality, particularly for people with low-end computers, so they're allowed if they don't include certain bugs that do indeed give players a visibly unfair advantage (such as the no-health-loss-when-falling bug encountered in the crashfix modification).