How about, what if a larger portion of Phyrrus fleet landed at Tarentum?
Hannibal kills the younger Scipio when his father dies?
Philip joins Hannibal?
The maniples are not detached at Cylescophele?
(i've got to go on hehehe)
Caeser isn't assasinated?
Something about Teutenburger Massacre?

Just suggestions from a rambler.