the super sukhoi MLU is all about adding a new cockpit layowt, AESA Radar & EW suites and a latest gen self protection jammers and the new and less mantainence oriented version of AL-41 engines as for RCS reduction not much than adding a new RAM coating and possiballi two new wingtip hardpoints
even if PAF gets a full squad of su-35 today it will still not be bettle ready as you need at least 2-4 years to make a new air doctroine around them while indians are parctising on MKIs/Su-30 for almost 15 years think about that too even if you forget ... khair janne do