I think in the current state of the game, units more of the Stiletto's weight and power are more useful, because they can survive a run early on, and be effective even if they die on their first run later on. It's easier to micro your 2 stiletto than your 4 pheonixes that take attrition damage and if they zag the wrong direction, miss all their shots and do nothing.
If I could think of a role for the Pheonix it might be to lay down a field of persistent DoT fire in a large AoE that has low upfront damage but can deny the use of an area over time (and would do full damage to buildings). We need more planes that have synergy with ground armies and offer strategic value, which is what I adore about the Stiletto, and a persistent DoT would allow you to deny an area and dictate troop movements. Sadly this would have more synergy with the old EMP Stiletto (that can keep them still in the fire) than with the current.
A problem is we might already have too much DoT fire at the moment, particularly when you consider what it does to Skirmishers and Raiders. I'd like the Firewalker and Napalm missile to also move away from huge upfront AoE damage and more towards a weapon which forces an enemy to suffer damage for staying in an area. Both these weapons are artillery too, so doing full damage only to statics is kinda the point. It can be hard to make the damage meaningful without nuking raiders, and this does mean assaults (except thugs) are virtually immune (Which is, IMO, ok).
With the current state of air, I just don't think there is a place for early game bombers. If there is, they would have to be more like the multirole: Resistant to enemy fighters early on and offering only a small amount of harassment damage to offset this immunity. Something like a fighter-bomber with a low damage bomb, or an ammo-based weapon that can target ground or air, or a ground attack plane with a long range EMG turret, or a bomber with boost, an armoured state, temp cloak (though I hate the counter structure, or lack thereof, there) etc. It would need to be geared more towards harassing cons, mexes, winds, raiders or turrets rather than comms, factories or armies: And it should not have the capacity to wipe out an enemies whole energy economy like the old pheonix rushes (Which was basically countered by people sometimes using e-cells, making the strat unreliable). If it is focused around comm-sniping, like the old shadow play, it should be around forcing a commander back, and punishing over-extension, rather than systematically destroying all the comms of an enemy who doesn't have fighter cover.