I'm sorry, I don't believe you got the real point of the set and I don't think you're able to convince anyone without testing it first. Sceptile is a RU Pokemon. It's NOT going to be something like SubSalac Terrakion or CM Keldeo. It's just a nice set that works nicely against common teams that aren't prepared to face it. This set is the only one capable of taking an advantage of Sceptile's Dream World ability while also being able to commonly defeat standard rain and sand teams. Look at Swimmin Pools
(by CTC) as an example. It literally has nothing to kill it and as long as you manage to put rocks on the field you will win.
Your comparison with Empoleon doesn't convince me either, mainly because Empoleon is slow, which means it gets revenge killed by common stuff (Scarf Keldeo, Scarf Terrakion, Scarf Thundurus-T, etc.) in rain while also having a main STAB that does not hit rain threats super effectively, although not extremely necessary.
Timid is better than Modest because it allows you to set up on almost everything in the tier. Sceptile's function in this set isn't wallbreaking, it's sweeping. It doesn't need full power because it can manage to defeat everything with Timid too. Of course there are situations where running Modest can be good, this is why I mentioned it in AC.
And about you saying that Ninetales and Scizor stop this set cold, is it really hard to get Ninetales and Scizor out of the battle? There are lots of stuff that can kill Ninetales and Scizor in the tier, it's not just because this set loses to them that it doesn't deserve a place in the analysis. You talk like every other Sceptile set could defeat them one-on-one lol