Most fighters are slower than most strike aircraft [reheating engines].
I get your concern though.
The only ones that you mentioned that can’t bomb without napalm are the Q-5A/Early, the A4s (which you shouldn’t bomb in), the Mig-27s if you want to keep your missiles, and the Alpha Jet.
Unless I missed one, all the other planes are able to easily bomb 1+ bases without the use of napalm.
I think the solution is to find a way to discourage fighters from bombing, either by nerfing the damage/damage type of napalm (i think it should take a lot longer to damage stuff than it does), preventing fighters from sacrificing missiles in order to take bombs, or decreasing the base respawn timer (but that doesn’t solve fighters bombing).
I also mentioned prop bombers.
If multi-role aircraft players want to use their multiple roles I have no issue with that personally.
If I’m in a slower aircraft, I’m usually targeting ground units instead anyway.