I play a vanguard as well, and believe it or not I've noticed everything you just described except for when I get the falling through the world bug I fly into space and can fire down upon my enemies from orbit.
I suppose I had something sort of similar only when playing on a laggy host, that I could tell was really laggy. No other times, but I also dont use the 25% chance thing. Never charged onto a rail so thats probably why. How would you even do that as enemies arent supposed to get onto rails either... Never seen this, maybe again when playing on a really laggy host? Again, never seen it and probably a laggy host issue Never seen that before either Again, sounds like a serious lag issue. You really might want to try deleting the game from your XBox and reinstalling, and also think about switching internet providers. Almost everything you said about bugs sounds like a serious networking problem. Its sounds pretty much like you are dropping packets so your network may be at fault.
negative on all lag fronts, and I play on the PC like a real person (kidding). Response in other actions while these issues occur (not all at once, usually I get one each wave a couple of time). To their credit, my connectivity is awesome and I get neither network or graphical lag impeding me. Also none of my normal crew have complained about latency on their ends during these. As for the rail charging, it's a result of charging an enemy behind cover. Depending on the angle of the cover they're using you can strafe a bit around them to get enough LOS to execute a charge despite them being fully behind cover.
I've seen enemies in the ground, stuck on roofs or rafters in buildings so getting stuck on rails seems plausible. However I have never got stuck when charging.
It's only overpowered on Bronze. You will die a bit in Silver, and die a lot in Gold. Then again, all classes do well on Bronze, so considering that, I'm not sure the Vanguard is that OP. I play an Asari Vanguard with a biotic charge/lift grenade/melee build, and I haven't had any bugs either
Drell Vanguard for me. Love the hell out of it. Charge, Pull, and Cluster Grenades get to ze killing for me.
Its easy to see why this is free, not only will it make people want to play more ME3 multiplayer for the new maps and stuff, but you will be required to buy (with credits or MS points) packs in order to get the new characters and weapons. And since everyone will want the new stuff, it will generate a lot of people buying packs with microsoft points. In addition it will garner more goodwill with the community because people bitch about anything if it isnt free. This method appeases the masses and gets them a lot of money without the masses realizing they are being retarded. Personally I am going to save all my credits from now till this releases and then spend them all on big specter packs in hopes of getting the new classes easily
I would guess it's because game companies, especially big ones like EA and Activision, truly care about each and every individual customer, and strive to provide endless, free content for all their titles.