this is not really a suggestion, for I can only guess how much work it would be to make a Refractor Engine internal port of PR from BF2 to BF Online. So, it is mere a information for the PR development team.
It seems that a korean company has upgraded the Refractor engine to be able to use more than 100 players.
From Wikipedia:
Battlefield Online (Korean: 배틀필드 온라인is a free online First Person Shooter developed by Neowiz Games, Electronic Arts and EA Digital Illusions CE, and distributed by Neowiz Games.[1] It is a remake of Battlefield 2. However, its game engine is not Battlefield 2's one, but Battlefield 2142's modified Refractor Engine 2, with graphic-improvements over Battlefield 2.[2] It is being developed by Neowiz Games of South Korea with oversight from license-holder Electronic Arts. Having started its 2nd beta test, Battlefield Online unlike Battlefield 2 has shown support for 100 player battles.[3] Its open beta test will be launched in the latter half of 2009.



