Stealth CAS means that the new aircraft will have its weapons in an internal bay. So that means a fatter design with smaller wings
Quite true... the real question however is what sort of stealth do they mean?
The Commanche program largely was cancelled when they realised that threats like Tunguska and then Pantsir-S1 didn't rely totally on radar for engaging targets so the Commanche, for all its cost in terms of development, the high cost of buying it, and the high service cost of maintaining its stealth, yet a widely deployed air defence system could engage it at ranges exceeding those with which it could retaliate.
Ironically the Il-106 had very thick wings and had weapon bays inside those wings for 250kg bombs... it also had a powerful main gun and a rear gunner position operating a tail gun.
The main problem is that for most CAS roles a couple of bombs is not enough... to be effective in the CAS role you need a decent gun... the twin 30mm cannon of the Mi-24, the GSh-30K I think would be ideal as it has a lower rate of fire but a higher muzzle velocity than the related GSh-30 of the Su-25.
After the campaign in Georgia the Su-25 pilots mentioned the rate of fire of the cannon was too high, so the gun on the Hind should be a better option with a high and low fire rate option and higher muzzle velocity.
You also need the capacity to carry large numbers of cheap rockets for use against area targets and light bombs are also useful for harder large targets or groups of enemy.
Some sort of guided standoff weapons would also be valuable but need to be cheap enough to use in large numbers and considering the direction the Russian military is going I would say a range of options would be needed.
I would say the TV, Laser, and IIR guided models of Kh-25 would be useful and the TV and IIR guided Kh-29s for really hard targets like heavy bridges would be good for unusual targets that are well defended. Add to that the Ugroza laser guidance kits for unguided rockets in the 80mm and 122mm rocket calibres would be cheaper yet very effective for small targets like trucks and APCs with HE Frag and HEAT warheads respectively. Finally the Hermes series of missiles would also be useful as it can be carried in large numbers and be effective against point targets because of their guided accuracy to compensate for the smaller 30kg warhead.
For bombs a mix of dumb and guided bombs is best with TV, laser, IR guided and satellite guided and their combinations would be most useful.
The most important stealth for a CAS aircraft would be in the IR range to make it hard to get a lock with a MANPAD like Stinger or Igla.
Obviously a self defence suite like DIRCMS would also make engagement with IR and optically guided weapons difficult too.
As you can probably tell this contrasts sharply with the F-117 which spends all its time flying at medium altitude and its primary weapon load is two laser guided bombs.