I agree that the rake length should be increased. Just pointing out some issues here.
The platform length increase was not implemented rigorously. Many of the major stations have long platforms, but the platform length has not been standardized across all stations. So you may have some stations on the route having long platforms, while most of the medium/small stations don't. This won't be a problem if it's only a few trains having longer rakes, but it will be a problem if longer rakes become the norm.
Moreover, just having a long platform...
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doesn't mean much. The signalling, fouling points etc also have to be moved so that the full platform can be used.
For example, one of the platforms at Secunderabad (SC), I believe it is PF3 or PF4, is long enough to hold 24 coach rakes. But the points (where the track merges with the other tracks) are too close to one end of the platform. So, some space at the end of the platform is useless, as there is a safety margin to be followed here. Because of this, the platform can only hold shorter rakes, despite being long enough. ( I don't know if this has been rectified now)
Similar issues may be present at most stations that seemingly have long platforms. This restricts the number of platforms that can be used for such long rakes, making things difficult for the controllers.
Again, not an unsolvable problem, but not a simple one to fix either, as it will require yard modifications at many places.

One more issue that rarely gets mentioned, is the capacity of the EOGs and the HOG. Adding more coaches adds more electrical load on these systems. They may develop unwanted harmonics (secondary characteristics in the power supply) because of the increase in the rake length.
This would be an even larger problem to handle as all the EOGs and the HOG systems in locomotives would have to be upgraded to the new specifications.
This is potentially an issue in this case as, particularly in IR, we have a tendency to always...
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implement systems that 'just' meet' the needs. We usually leave very small margins for updates and expansions.
Most stations have platforms and loop lines that are 'just' long enough for the longest rakes of that time. The locomotives are typically just powerful enough to handle the largest loads of that time.
It is such philosophy that is the main hurdle in transitioning smoothly to newer technologies, and optimizing operations (in this case, increasing the LHB rake length).

Yes, I know these problems. Which is why I mentioned attaching a couple of coaches in the busy season, not as a permanent basis till such lacunae are rectified.
Power may not be much of an issue for mixed rakes as only one EOG is used. It may pose some problem with full AC rake with pantry. Presently, P7 power capacity is being ramped up by 500 HP. It may be in line with providing more power with HOG. With 100% track electrification in sight, next couple of years might see most trains with electric power end-to-end.
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platforms at major stations do have required length from where most popular and prestigious trains operate. What I suggested was attaching couple of extra coaches to such trains only in busy seasons when wait list turns into regret.