So you know the reason already why I say, don't start over and redo everything.Ogre3d lost all momentum when going for 2.0 and never really recovered. Neoaxis went for 2.0 and has seemingly died a death. Even massively popular projects with a huge community like AngularJS for example have lost loads of ground by trying to reinvent themselves too much.
Torque is more complete and proven than probably any other open source game engine, I think the other open source projects are just not very intelligent, they try to make something work and promise features in the future that of course almost never happen, that all already exist fully functional in Torque for many years, it is basically a total no-brainer what engine to use in that case, yet everyone wants to cook their own soup and start all over, leading to eternal development hell.
And regarding C#:
Microsoft was always hostile to open source, they just changed their strategy in fighting it, I would not want to play russian roulette on that and use stuff from them and that was just one argument, the other arguments are that the benefit has yet to be proven, for example I remember testing a Torque built in C# and the performance was indeed by a huge amount better, at least in the small test scene he had, when I loaded it up into my loaded scene, the performance was about 10-20% less. So overall I could not see a benefit in there performance wise.
I would rather improve Torquescript, I saw a post somewhere where a guy improved Torquescript so it ran up to 50% faster, if we can figure that out, that is a far better promise than to gamble with other scripting languages and hoping they do any benefit.