Comparing the A-10 to the strike eagle and F-16.
F-16 can carry two GBU's and 510 rounds of 20mm max and it's endurance still isn't great.
F-15E, incredible platform, can deliver 8 GBUs and 940 rounds of 20mm with an excellent endurance. However, a 500lb bomb is sizeable, a tough enemy 40m from you and the vulcan won't cut it.
The A-10 arrives, 4 GBUs, 1150 rounds of 30mm, possibly two rocket pods, the same targeting pod as on the Mud Hen or F-16. Excellent endurance, slow, easy to fly while getting ready to shoot. Resistant to just about everything you an throw at it. I know which one I prefer.
Also, the sheer rate of fire from the GAU and the PAC control means when you're attacking tanks it's preferable to be in the A-10. Show me a video of you destroying a T-80 or Abrams in a single burst with the Su-25T. EDIT: SADL and TAD anyone?
Another EDIT: The maverick seems to be a far more reliable weapon than the vikhr and being fire and forget you don't need to continuously dive in on a defended target so your missiles hit, you can shoot from 5-6 miles and then turn around and leave.