It's true in PvE you don't really need (or want) to go past the Viper. In fact I would argue the Python as it is is also useless for PvE because the fuel costs and repair bills are enormous. This is more of a problem with AI and mission balance rather than a specific ship.
If you're saying you want a reason to go past Viper for PVP combat, I seriously doubt all the Cobra and Asp PVP pilots flying around agree with you.
The Cobra is within the price range to be reasonable(Two days of play, lordy lord) and the Asp is so marginally better then the Viper you need to shell out 20 million to make it happen *Suddenly a month of combat play* (40 more shield strength and anther set of class 1 guns)
The Python as it is now is almost good enough to want to work for, but after this its just another trade ship. Even then, outfitting it for combat from an Asp is from 20 million to 120 million, if you are truly interested in bring it to combat.
For the time investment, nothing is worth it past the Asp. The game is balanced around a stick that is only an inch long.
Yes, the end is nigh! Surely, if you make one ship slightly less agile than sidewinders will one-shot everything! There is no hope for the human race!
The announced Vulture seems vastly superior to the Viper, and it is intended to be so. The Viper is terrible at exploration due to limited jump range, and due to limited cargo it isn't much for piracy or mining either. Why do so many people lose all perspective when one ship gets tweaked a bit? Just say:"currently the Viper is the only dedicated combat ship, I want more/better ships for that." That would actually make sense, and FD announced they will change that.
Another ship for around 10 million or so does not address the base issue. Even if its straight up better then the Viper, the goal post is only going to shift a foot into the correct direction. There would be no reason to go past it instead of the Viper.
The one inch stick becomes three, wile traders can enjoy a fully fleshed out ship selection and credit scaling.
Hauling goods from one station to another without anything else for the rest of eternity.
These are the kind of things that should be looked at before PVP balance can even be considered.