Advantages also include -
STOBAR capability,
cheap,
very high flight ceiling meaning better OTH coverage,
high endurance, esp. if equipped with EFTs, and AAR capable
possibility of side arrays
possibility of rear coverage although not heavily needed since we are talking of two planes airborne flying behind each other at
possibility of L band coverage via t/r modules on the wings ala pakfa and Su-35
The above possibilities are not "paper" capabilities but have been demonstrated to some extent with the flanker (except the side arrays). By the time we are looking at operationalizing a 65-100K ton carrier, there should be a lot of improvement in TRM capability with the proliferation of GaN modules - a lot of the past limitations in power output and coverage might be addressed.
You do realize that none of the sensor solution you mention would provide any sort of AEW capability in the long range surveillance sense?
possibility of side arrays
So the Indian flankers can get side arrays? And how will they add tot he radar coverage in terms of range? Finally, whats the range/payload penalty of the flanker taking off of from a IAC-1?
possibility of L band coverage via t/r modules on the wings ala pakfa and Su-35
You will still run into physics.
By the time we are looking at operationalizing a 65-100K ton carrier, there should be a lot of improvement in TRM capability with the proliferation of GaN modules
GaN is not a magic bullet and won't give a fire control radar setup magical long range surveillance AEW capability. There are qualities which make a particular material and a particular radar setup suitable for a particular task. You unfortunately, cannot take the longest range of an FCR, superimpose it in the 360 and claim 360 degrees surveillance capability on an AEW orbit. Unfortunately, it does not work that way. Even with dedicated AEW's, with their dedicated sensor choices, you still have very heavy processing, different modes and a mix of all electronic, or mechanical and electronic scanning to meet the performance requirements in a dynamic environment, where multiple mission needs compete for resources (frequency choices, IFF choices, processing choices, and computing capability..and of course workstations and people to control and manage that). You can't tilt the requirements towards one aspect (as is done for a fighter) and then claim a legitimate AEW capability, in the 360 degree no less, with any deal of sincerity.
the EMB145 has a antenna with some 15 feet length and probably lot more power to radiate.
The radar frequency chosen lends itself better to very long range surveillance mission with obviously the challenge in processing that took years to hammer out. There is a reason why on the E-2D they stuck with a UHF ESA and why Northrop paid Lockheed nearly half a billion USD to develop tit instead of an L Band AESA, that northrop (and Lockheed) itself has been producing for various applications for some time now that they could have repackaged for this particular application. Mission requirements (low RCS cruise missiles, and aircraft plus very Long Range for stand against incoming sea skimmers) drove them there. Similarly, for land launched, Raytheon ( which incidentally also was a Lockheed team member and worked on the E-2D antenna) was driven towards a VHF (AESA) airborne radar for a similar mission (anti low flying -low RCS cruise missile defense). You can choose a higher frequency of course, but mission requirements (and other design requirements) and what within these get priorities drives these towards a certain direction.
For the current mission, the E-2D with its 24 ft diameter antenna is more than adequate since it gets around 2.5 times greater coverage than the AN/APS-145 it replaces. Of course other design trades could have dictated other design decisions. Had this been a land based aircraft, meant for mostly land based or littoral ops, perhaps they would have gone in with a much much larger higher frequency sensor but its maritime and littoral conditions, and USN's mission requirements against particularly the cruise missile threat (which also lends itself nicely to LO and VLO targets since the challenge is similar - small radar returns which particularly tend to get lower/smaller the higher up you go in frequency) is what drove the current trades. Net Centricity (CEC), and the DL nodes it carries would have ported over regardless of the sensor choice.
You can't really compare the E-2D and the EMB145 AEW unless you have a mission in mind and have some pre-set conditions that you value more than others. The E-2D is first and foremost a carrier based AEW, with a lot of focus towards maritime fleet defense challenges with littorals in mind as well. The EMB145 as a pocket AWACS will perform much better than the E-2D that has other roles that really drove its design requirements and sensor trades.
if the task force is 1000km out, you can do the math of keeping 2 flankers over it 24x7, you'd need a refueler to use them properly, and planes in transit to and fro from land base to keep things up ... and multiple refuelers....its simply not viable vs a simple organic KA31AEW solution even.
A fighter based FCR enabled AEW orbit cant really be called AEW capability..but as I said earlier, I am happy to play along

But one question still remains unanswered : Can a modified Flanker, with a FCR like performing 360 radar and a centerline SAR pod, plus some weapons (I would assume) or fuel tanks (have been suggested) take off from the IAC-1 and if so, whats the TOS like say 300 km from the carrier given the maximum fuel state with which it can indeed take off?