Managed switches don't have anything to do with how data is arranged in the PLC or the WW PC. Switches just pass data packets from one port to the other, they really have no idea what the data means or how it will be used. All a switch is concerned with is where the packet should go.
If you group your tags in arrays in the ControlLogix, you will save some processing overhead for both the ControlLogix and the WW PC driver. That is where packets are formed and redistributed.
With more processing power available in ControlLogix and PCs, this is less of a concern.
Older systems like the PLC5 with RSLinx used a very simple method of forming packets. If all your tags were in file N7, it would simply make a packet for N7:0 to 99, and another for N7:100-199, and so on. If you put all your tags in N7:0 - 99, you got 1 packet. If you had one tag each at N7:13, N7:133, N7:249, then you got 3 packets. So grouping definitely made fewer packets.
The ControlLogix is much more complicated than that and makes packets as needed. It packs different tags into the same packet, this reduces the number of packets, but the more tags it has to keep track of in each packet, the more work it does. It is much easier to read/write a single dint array of 120, than to read/write 120 separate dint tags when sending or receiving a packet.
However, it does a pretty good job of it, and as long as you aren't having issues, I wouldn't worry too much about it. If you are planning to move massive amounts of data, then making it as easy as possible for the hardware may be a good thing.