So, I doubt that a big update for halo 5 will come, but some things could be patched. One thing is that if an option for a specific vehicle to support passengers only/drivers only kind of like the vehicle camera option could fix some issues with vehicle welds. The mongoose is my go-to for a chair on a welded vehicle, buf you cant really tell everyone that getting into the driver seat of said vehicle will glitch or even crash the game, if the parent vehicle has a driver already. So, maybe only the parent could have a driver? Please fix if possible 
Another issue is that welding more than one vehicle that is not the mongoose also makes welded groups bug and flip out literally even when phased or fixed. For instance shade turrents on a weld with a banshee as the parent object or phaetons with any welding too. We need smoother welding for vehicles so that we can have some awesome creations.