SBC - Kranti Veera Sangolli Rayanna Bengaluru: Station in Garden - Dinesh Kumar

Kerala or more precisely the Railway Unions and Associations of Kerala, do not want to end up with one railway division, which was why they were opposing the formation of Salem division tooth and nail two decades ago.

Multiple divisions translate into more job opportunities and division-wise resource allocation for the ancillary sectors that generate plenty of indirect opportunities for the locals.
...
more...

In the past, Kerala's priority had been getting an independent zone outside of SR, and they were pushing for it when SWR, NWR, ECoR etc. was formed. For that end they wanted to hold on to vast sections in Tamil Nadu that would go to Salem division or the (proposed) Tirunelveli division.

It is a different story how PGT and TVC divisions were the earliest beneficiaries of railway development in the undivided SR days (on par with MAS and SBC), and later some in Kerala would be calling out SR on not giving importance to their state and would be opposed to giving up Nagercoil or Pollachi as a tit-for-tat.

Kerala has failed to add new railway lines and their people are not enthusiastic regarding alternatives like the Silverline project. Its existing lines have reached saturation and further development would be a challenge for any entity (SR or otherwise).

On the other hand, you cannot go on ignoring the cases of persistent grievances faced by Mangalore, Nagercoil and Pollachi (nobody talked of it as long as it was under MDU division and its demand has been the mere restoration of the MG era services).

As there is no chance of Kerala zone materializing, or even if it could be sanctioned as an SPV like KR or Kashmir railway, the best thing would be to redraw the divisional boundaries to best serve the needs of the public than satisfying bureaucratic arrangements.