It's a good idea for new players to play against other new players. But, you don't need to create a new server for that. Going with this threads suggestion, I think it's a better idea for them to:

• Change matchmaking to pair those whose accounts were created less than 3 months.
• Give the option to opt-out staying in the "New Player Matchmaking Algorithm" for those that wants to move into the regular matchmaking sooner.
• Regular matchmaking starts after 3 months end.
• Lockout mechs and weapons not fitting the new player criteria (i.e. uncommon green hangars or less are only allowed). This lockout is lifted when either the 3 months period ends or the player opt to start regular matchmaking.

Going this route needs less technical work than creating a whole new server and transferring players from that server once 3 months have passed.

good idea but SP droppers creating new accounts for some reason.. especially for SP dropping.. so there is no escape

Limiting what type of mech and weapons that can be used for new player matchmaking will deter most SP droppers. I doubt you can do much having only common and uncommon hangars. 

thats true :) can i play it then also? ;) 

If you create a new account after every 3 months and being happy with only playing grey and green mechs/weapons while not being able to experience better capability hangar or any new releases. 😛