This rod gets pretty good reviews for jigging. Any thoughts if this could also double as a frog rod?

No experience with that rod. First impression is 7’8 is long for a frog rod and Dobyns 4 power is weak for a frog rod.  I’m sure you could make it work if needed or if you just frog in occasion. 

I agree with GReb on this 4 power is weak for frogging. The Dobyns XP DC 736 FH is a excellent rod for frogging & is a 6 power.

^ Consensus - 4 power isn't stout enough for frogging, you'll want a 5 power minimum. @scbassin's recommendation is a good one...about the right length and good backbone.

I’d go champion 705, 735, or 736 depending on what cover you’re frogging. I love the 705 for moderate short range frogging. Easy on the wrist.

The 784 is a football jig, Carolina rig model.  It lacks the mid blank power to be an effective frog rod.  If you want a duel purpose model the 705, 715, 735, 745, 736 and 746 models give you better options.