I doubt it honestly. For events/tourneys you could probably get a lot of people to switch over, but for regular play? No. Your average casual player will just hop on NW and play. They wont know about the new "mod", know how to get it and may even not be interested in playing it. Sure you can advertise for it and do a big marketing campaign for it but that wont reach everyone.(and maybe not even a majority of the active pub player base. this isn't even counting steam sales where people will just get the game and log on) Combine the 2 points above and all you do is split the community. The casual side of the community is small enough as is. If it gets any smaller, people will have a harder time finding a active server to play on and enjoy.
It may just end up killing the game faster. Sure, you will still have events but as the game goes on, regiments wont have as many new recruits replacing inactive members which in turn will cause them to slowly disappear. and this will lead to other issuse.
or perhaps i am wrong and dont have enough faith in people being able to mass shift to a "new and improved" nw to avoid most of the issues. This would still have issues around steam sale time.