Seriously? It's not just the 6 yards, which is a big deal, but also the difference in who controls the timing and the difference between a still ball and moving ball. The IFK is a huge advantage over even a modern DB.
(I've said on here before, I'm not a fan of the new DB for a variety of reasons. I think the TI/GK would be better than what we have now. (But I'd still go back to the old DB if I was the grand poobah of the Laws; but I'd also permit the referee to permit (but not require) a player to commit to a sporting restart and caution him for violating what he agreed to.)
A PK for 6 second violation! More seriously, I'd be OK with going to DFK for everything except GK violations. (And I wouldn't mind getting rid of that crazy near goal IFK (nothing I like less than managing those IFKs less than 10 yards from the goal) by going a step further and saying a GK results in a CK, or we could borrow from field hockey and have it be a "short corner" from the edge of the PA.)