I think the issue is not enough ships within a certain class. The cobra is 3x the cost of the viper, you can't really compare it. You get what you pay for. FD has been adding ships at different price points but hasn't really done much to add variety of ships within a specific price range.
What would be really cool is if FD will allow us to mod these ships past their original spec, albeit for exorbitant prices and/or sacrifices in other areas. So for example, pay a few million to upgrade a hardpoint or internal slot rating, but besides the cray price also have to deal with increased mass and the issues that will cause if you don't likewise upgrade the thrusters. etc. There's a whole new level of meta gaming that could be added with a ship mod system.
What would be really cool is if FD will allow us to mod these ships past their original spec, albeit for exorbitant prices and/or sacrifices in other areas. So for example, pay a few million to upgrade a hardpoint or internal slot rating, but besides the cray price also have to deal with increased mass and the issues that will cause if you don't likewise upgrade the thrusters. etc. There's a whole new level of meta gaming that could be added with a ship mod system.