I think using composite material will reduce it's weight further & if automation is increased from 180+13 to 80+10 like P17 to P17A as 90 sailors is almost standard for such ships, what do you think.
Recently GRSE offered two frigates to Philippines Navy(may be based on P28) can be used for a light frigate.
Use of composites doesn't necessarily solve topweight issues, which deal with where the centre of gravity of the ship is and how high up there is significent weight. See Sa'ar 5: it never sailed with the 2x32 Barak AND 2x4 Harpoon AND 2x4 Gabriel for which it was designed (and with good reason).
Shivalik class has a complement of 257 (including 35 officers). This will be reduced to about 150 total in P17A. If you project that reduction ration onto the p28 complement of 193, you get 113. I don't know what you mean by 'such ships': what ships are you comparing to?
2 x
RBU-6000 ASW rocket launchers designated as IRL (Indigenous Rocket Launchers). Each launcher is 12 barreled and has a reload of 96 rockets under the deck. They are retained because of their hardkill ability and immunity against countermeasures. These rockets have a range of 4500 m and a shaped charge warhead which can be set to explode at a particular depth. It can punch a hole in the hull of a submarine or be used to defend against an incoming torpedo. The rocket, after it is fired, reaches the required location and falls in the water where it sinks until it reaches its target. Usually, 24 rockets with various warheads are ripple fired against the incoming target to achieve maximum kill rate.
Source
So, I think there is much space below RBU-6000(may not be full for BrahMos, I don't know if height can be raised or not), another thing is in Talwar BrahMos is ahead of RBUs so that may provide more space for 8xBrahMos also there is only one RBU-6000 on Talwar.
Magazine capacity varies, typically 72 or 96 rounds per RBU-6000 launcher. The launchers itself weighs 3.1 tons. The classic RGB-60 projectile weighs 110kg and the more modern homing 90R projectile weighs 112.5kg.
So, at set of two launchers, each with their own reloading mechanism and magazine weighs between 2x(3100+(72*110))=22040kg and 2x(3100+(96*112.5))=27800kg.
The 8-round UKSK-Kh launcher weighs 14 or 15 tons, depending on subtype. Each Brahmos missile weighs 3 tons. So, a set of 8 in a VLS would weigh 28-29 tons.
The arrangement of RBU and Brahmos systems on P17/Shivalik isn't all that different from that on project 1135.6/Talwar. With a beam of 16.9m and draught of 4.5m, P17 is about 1.7m wider and has 0.3m greater draught relative to 1135.6. For Delhi/P15 and Kolkata/P15A this is 17.4 m and 6.5 m. Kamorta/P28 has a beam of 13.7 m.
As late as may 2015, Janes reported on P28 that:
In due course, the corvettes will be fitted with an Atlas Elektronik towed array sonar, the Israeli Barak 1 missile system, and the Indian-developed Mareech Anti Torpedo Decoy System.
http://www.janes.com/article/51550/grse-launches-fourth-p28-corvette-for-indian-navy
The Kamorta Class is installed with a 16-cell vertical launching system (VLS) for firing Barak Surface-to-Air Missiles (SAMs). The Barak SAM system can strike anti-ship missiles, fixed and rotary-wing aircraft as well as UAVs.
http://www.naval-technology.com/projects/kamorta-class-asw-corvettes/
Ok I remember one quote of our scientist about Brahmos. He said that Brahmos has a potential to stop the war. It is such a potent missile that if you have that in your arsenal than enemy would noe like to mess with you. If Vietnam is in a condition to inflict some collateral damage to china, they would not prefer to mess with you. for that , you need to be reasonably strong.
Why. Existing systems have been able to intercept supersonic missiles for quite some time, e.g. Goalkeeper and ESSM. People keep forgetting the Russians have employed supersonic missiles for a far longer period than the existence of Brahmos. And, besides, supersonic low level penetrating aircraft are just as dangerous (if a larger target). The only issue with supersonic missiles is the decreased response time, as defender you want to detect them as far out as possible and engage them as far out as possible. That's where the challenges are and that's why you get e.g. an 11km SeaRam replacing a 3km Phalanx on a one for one basis, or ESSMs on board the Arleigh Burke.