Actually MiG29 was frontline fighter rather than real interceptor, and as such it lost alot of its real value post 80s, thats one of the reasons why many pure fighters were phased out of service though time or got modernisations that added air to ground, recond and similar capabilities.
In the Soviet/Russian air defence system a short range fighter is still an interceptor... the only difference is that sometimes it will patrol airspace to intercept any enemy incoming threats from cruise missiles to fighters and bombers and of course fighter bombers.
Considering it will have two large AAMs and at least two smaller AAMs... normally R-27Ps or R-27Rs or a combination of the two, with at least two and often 4 R-73s as a standard weapon load I would suggest there is little leeway for alternative air to ground ordinance like guided weapons or dumb bombs.
Actually T10/SU27 platfom was always outperforming MiG29 in almost every aspect, except operating costs and initial price that was always higher. There is a reason why no new MiGs havent been obtained for 2 decades now basically in RuAF. MiG had its big place in USSR doctrine however today i dont think so, id rather fit 1 engined multirole fighter in its place in RuAF but atm such platform does not exist, maybe in future.
It was never anything to do with performance and everything to political influence. Sukhoi dominated the post Soviet period and MiG floundered because of lack of the export success Sukhoi enjoyed.
Good replacement for MiG25s could be SU35, as they do not really need "real" interceptor but rather multirole fighter with significant air superiority capabilities. Again sharing same platform T10 with SU30 would fit the profile of saving costs. I can see the point of US, Russia, China, India... operating multiple way different platforms (even tho India is going abit over the top) however i dont find justification for Algeria.
The real issue is what do they want... by having different types for different roles they can optimise their capabilities and costs. If you are going to buy a car for everyone in your family then do you just buy expensive sports cars for everyone? or do you buy a cheap second hand car for the learner drivers going to university, a cheap run around stationwagon for the wife to get the groceries and cart the kids to sports or wherever they need to go and a soft top sports car that would have cost a fortune new but is cheaper to buy now it is 30 years old for you.
Do you think a sensible people mover for everyone makes sense... cheap to run and of course able to carry everyone if needed... all the same engine and tires and batteries and parts... from an economic position that is what you are saying... but in the real world new drivers get cheap cars, mum gets a people mover that will cart around kids and their friends and do the groceries on the weekend, while dad gets either a sports car or a nice modern sedan.
The irony is that suggesting Algeria can't afford to have the right plane for the job is amusing... these aircraft and the weapons they carry are f*ing expensive anyway... the few dollars you might save having all the same type is lost when that company has you by the balls because the other aircraft makers have gone bust because the maker you went with now dominates the market.
Sukhois are generally good value for money but ask India about upgrades... brand new technology is NOT cheap. Having alternative options is a good thing even if your accountant does not agree.