I have a G Loomis MBR784C, a 6'6" rod, which I use for jigging and worming. I'm considering switching to a MBR844C, a 7' rod for improved hooksets and versatility. I know about the general differences with casting accuracy but would like to know what changes to expect when working my lure - rod weight, balance, etc. Thanks.  

I think you will find the 7' rod to be just as manageable as the 6 1/2' Loomis you are now using. Initially casting accuracy may be an issue, but that will come with time. Casting distance will improve slightly.

The overall "feel" is comparable.

If or when you switch I doubt you ever look back.  I've never understood this theory on better accuracy with a 6'6" rod over a 7' rod.  I can cast both the same.  The benifits of a longer rod outweigh the disadvantages.  From your earlier posts of fishing thick weeds this is where you will notice most of the difference.  Your 7' will give you more power to get those fish out of the weeds.

There are only 2 things I use a 6'6" rod for in bass fishing.

1. jerkbaits like xrap, rogue

2. fishing in tight spaces.