Absolutely brilliant post and idea. Something that has made sense to me for a long time.
1. The utility of such a CAS platform would be that, in a war with India, even with heavy losses, it would have a decisive impact on the front. Large and concentrated formations of forces would be decimated. Remember 71 when PAF was willing to sacrifice its expensive and hard to replace jets to help the ground forces? You simply don't need that - you use a dedicated CAS aircraft instead.
2. Army budget vs air force budget is the issue. If we think of it in terms of reducing PAF focus on air defense, the logical answer is the CAS aircraft is a no-go. If we think of getting 10 tucano type aircraft (perhaps a Chinese eq), instead of x number of new tanks, the value proposition is very attractive. Far more effective at thwarting an armored thrust and utilizable at multiple fronts at short notice.
3. Recon role during peacetime. Maritime role. Anti-UAV role (which seems to keep crossing the border). Why is peacetime even an issue? An F-7PG is excellent for intercepts during peace time, so why is the F-16 needed? Equipment is bought for war time requirements.
4. Use in low intensity conflicts would be immensely useful. And these kind of conflicts wouldn't stop anytime soon given geopolitics.
5. Tucanos in exchange for JF-17s - an offer Brazil would be hard-pressed to refuse given their dire need of fighters.
6. The main thing about an AC-295 or similar is they have great loiter time and immense firepower.
@Oscar is perhaps thinking of CAS as a short loiter trainer type. But a proper CAS aircraft has excellent loiter compared to a trainer or a "multirole" fighter.
But large CN-295 types, they would be sitting ducks against India in a war. Using them as transport would be of minimal benefit in a war.
Bottom line is a simple, cheap rugged CAS aircraft would be a major detterent against an Indian armored thrust, "cold start", "luke warm start", whatever. The logic hasn't just been thought through yet.