Yeah, but background reasonings for their actions aside wouldn't both of them still amount to the "former friends now arch-enemies" schtick?
Venom having the Goblin's schtick (knowing Peter's secrets and neutralizing the Spider-Sense) was okay when he was introduced because by then there hadn't been anyone who knew Peter's secret as a villain for years. Unless something happens to get Venom out of the series having both be around at the same time will make one redundant.
Then again Venom seems to reply more on pure power and never thought about revealing Peter's ID, whereas Harry's torture of Peter was most psychological/emotional (Robot Parents anyone?) and he was always threatening to reveal his secrets with Peter unable to do anything about it.
Venom would have ran his course by the time Harry dons the goblin costume. Its not that bad. There have been many similarities, coincidences, and redone schticks in the Spidey universe (JJJ creating or funding superviallians like the Scorpion and Spencer Smythe, many Daily Bugle employees being supervillains themselevs or having ties to the criminal underworld, having multiple villains who have similar powers or similar backstories or similar goals).
Also, did you know that, either by chance or on purpose, when Marvel finally gave Eddie Brock a detailed history, it parelled Harry's history almost perfectly?
1) Both Harry & Eddie had uncaring fathers. The two boys/men would grow up doing everything they could to impress their dads, but nothing was ever good enough.
2) Both Harry & Eddie's mothers died during or after child birth.
3) Although its never revealed what Eddie's father did for a living, it was obvious that Eddie's dad was wealthy, same as Harry's dad. All that money, and no fatherly guidance.
4) Let's not forget that the Eddie/Peter relation also exsisted in the Ultimate title, as well as the Harry/Peter one.