You must writhe in ecstasy

Power level is relative to the army it in and what it goes up against. The former is for army list creation and trying to ensure all the armies units being a valid choice, and the latter is to put them in a hierarchy of power as it were with other races. Actually costing it comes after that, with any necessary stat changes if it proves too hard to balance (good example is high firepower low survivability units, epitomised by the deathstrike). Yes we could have an Eldar fighter with just one 6+ attack and point it accurately, likewise we could have Imperial Guard with 4+ armour saves and balance them within their own list and point them fairly. But Eldar fighters are the best plane for plane, so get the abilities and firepower to show that. Guardsmen wear trenchcoats and carry flashlights and get beaten by space marines, so the stats show that. The points then follow to try and mitigate the advantages and disadvantages and provide a level playing field.
Why talk? Because people got sick and tired of just testing stuff for epic a long time back, and most thought it a waste of time ultimately. Especially through stuff being in lists that was so obviously broken (which is a different issue to this, no one is saying the air superiority Helltalon isn't balanced). I'm down to what 4? people I can easily get to or that play against each other and are willing to test stuff, thats down from about 2 dozen. So the stronger the unit on paper, the more 'right' it looks (and this judgement is always made in comparison to other armies units as well as its own) the more chance I can actually get people to play with/against test armies. For Epic I've always been of the what has the model got, what's its ability level relative to its peers both in and out of its list and finally once thats sorted whats the starting points level for playtesting?
But all this is moot. The planes better than the Imperial stuff, not better than the Eldar, has the stats to match that intended power level and those have indeed received a fair bit of testing, just have to try vs some marine air drop or other air reliant armies to see if they should be 225 or 250.
_________________
If using E-Bay use this link to support Tac Com!'Abolish red trousers?! Never! Red trousers are France!' – Eugene Etienne, War Minister, 1913
"Gentlemen, we may not make history tomorrow, but we shall certainly change the geography."
General Plumer, 191x