The +1 attack bonus is for "higher ground." By RAW, you don't get it simply by being at a higher base than the foe, you actually need to be on a solid surface. So, if it were a small hill or the back of a horse you would, but not by jumping up or even by using a fly speed to hover over the ground. Again, this is just the RAW, some DMs might allow it. I wouldn't, if it matters, because like you demonstrate, it's a little too easy then.
As for falling distance, I think RAW is that it counts as part of your movement. So if you don't have enough movement left to finish falling, you fall as far as your remaining movement allows, then finish it at the start of your next turn. I don't particularly like that ruling, it leaves open questions as to whether you can take actions to stab at someone who's free falling beside you if by the rules you're devoting your turn to movement (falling). But I believe that's the rules as written.