Well, Shinsen's HD release tempted me again....
Everything's been said pretty much...just a few things I might add:
1) Being able to replace the arm isn't really the issue. I can imagine a wedding nowadays, and the bride has to use a prosthetic hand. Not being able to feel the ring being put on is a pretty big emotional hurdle.
2) Regarding Trinity's seemingly armed interventions, they seem to be taking orders from the Veda counterpart they call Lagna, hence which may explain how they hacked Veda with relative ease. I'm thinking that it was Nena who hacked Veda, and changed the data at level 7. The solar furnace blueprints were already on evil Haro, and they just worked off that.