I spent the entire day figuring this out on my MacPro4,1 (2009), so while I still don't know whether it's better to format each drive as HFS+ or LVG, I can answer your original question!
"can't figure out why when I initialized the 4 TB drive it defaulted to a Logical Volume Group"
Yes, since Lion this is the default filing system, and yes, you can format your drives as Journaled HFS+, no matter the size.
I freaked when I learned about the fusion drive as I had just extracted my DVD drive and installed 2 Samsung 120GB Solid State drives in the Upper & Lower bays. I was primarily worried about Core Storage being in charge of my roughly 10TB's worth of animation & graphics resources and feared I'd sooner or later encounter some failures when CS tried to copy video sources during editing... transferring 50GB of files to the SSD for a single project scared the s out of me, so I wasted a day figuring out a procedure.
Monday: two 120GB SSD (Upper & Lower Bays) | three 3TB Seagate Drives (SATA in Bays 1-3) | one Seagate 4TB (SATA in Bay 4) | all of which were formatted as LVG's
Thursday: all drives formatted as Journaled HFS+
Method:
1) backup a drive
2) shutdown
3) extract drive from bay
4) restart
5) connect drive externally (should come up as unreadable and ask to initialize)
6) click Initialize or just open Disk Utility
7) in the DU window, select the drive (not the volume underneath)
8) click on the Partition tab
9) select 1 Partition from the pulldown menu
10) click the Options button
11) click the GUID radio button, then OK
*You couldn't reformat the drives because the partition scheme of all LVS-formatted drives are Master Boot Record, not GUID. Furthermore, when the drive in connected in the bay, the LVS prevents you from re-partitioning the drive)
12) select Mac OS Extended Journaled for the format, name it and click Apply
13) after formatting is complete, quit programs and shutdown
14) install drive back into bay
15) restart (the disc, even though formatted as HFS+, will come up unreadable so open DU)
16) for some reason, the bay interface doesn't like the externally formatted drive, BUT since the LVG has been deleted, you can now move forward
17) select the disk (not volume), click the Partition tab, select 1 Partition, click Options and select GUID and OK, select Mac OS Extended Journaled, apply and voila!
Follow-up Q's: So now that we can create HFS+ drives and eliminate LVG's, it begs the question, does having multiple LVG drives open the door for the OS to fuse them at some point automatically? Since my SSD drives are HFS+, I assume this is not a worry. But now, I'm wondering that if I have 4 drives individually formatted as LVG's, will each drive remain discrete? If so, then is the LVG format way better than HFS+? If so, why? Or did Apple just start using LVG's in anticipation of fusing SSD & HD tech? All I wanted to do was prevent the OS from spreading my data across multiple physical drives, so if LVG is tons better and each drive will always remain completely separate, I'll switch back... hopefully someone will answer before I've copied all the data to the fresh HFS+ drives:)