May I ask for a top 3 paid file transfer UNIX utilities to improve : automation, ease of use, and improve speed compared to BBFTP?
BBFTP is an inconsistent, unsupported, high maintenance file transfer tool. At best, BBFTP has proven to transfer an average rate of 20GB/Hour Total (with 4 concurrent workstreams) between 2 datacenter.
We need something that can be installed on the client servers just like BBFTP, literally �a server-to-server file transfer�. 
You can use CFT or Connect Express
How fast is the WAN connection(s) between the two data centres? Is it a leased line, cloud network, satellite link or what?
What is the distance between the two data centres?
What transfer rate do you desire?
Ps. Based on the figures supplied I estimate your current line speed at 56 Megabits/second .
I agree, and 54 megabits per second sounds like the speed of a maxed-out half duplex 100baseT line. Or it could be a saturated bus or a disk speed problem. Or a variety of things.
The one thing I don't believe it is, is a software problem.